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Satellite-derived bathymetry and rock detection for maritime archaeology using VENµS
imagery
Gerardo Diaz1, Dr. Yoav Lehahn2, Dr. Emmanuel Nantet3
1
Department of Bible Studies, Archaeology and the Ancient Near East. Ben-Gurion
University of the Negev, Be’er Sheva, Israel, PhD Student.
2
Department of Maritime Geosciences, Leon H. Charney School of Marine Sciences,
University of Haifa, Israel, Senior Lecturer.
3
Department of Maritime Civilizations, School of Archaeology and Maritime Cultures,
University of Haifa, Israel, Associate Professor.
ABSTRACT
Since its beginnings in 1975, deriving bathymetry by means of multispectral satellite imagery has been a method
that has not yet been fully exploited in the maritime archaeology realm. It focuses on using the blue and green
bands for their water penetration capabilities to later convert each pixel into depth values. This method can be
replicated in time and space, while keeping costs low and covering large areas. In this research, two highresolution bathymetric maps using VENµS satellite imagery and a variation of Stumpf’s equation were
produced. Two archaeological sites were selected: the harbour of Sebastos (built by King Herod) and the Achziv
ridges on the northern coast of Israel. The importance of collecting satellite imagery under low Chl-a [mg/m3]
conditions is addressed, and an algorithm for identifying shallow rocks above and below the water level is
included. Our research suggests that satellite-derived bathymetry mapping along the Israeli coast is more
efficient for satellite images taken between March and September, when Chl-a concentrations are likely to be
lower; maximum depth penetration using VENμS is found to be approximately up to 23 m depth with a Root
Mean Square Error (RMSE) of 0.53.
Keywords: VENμS; bathymetry; chlorophyll-a; rock identification
List of Abbreviations
Red, Green and Blue
Satellite-Derived Bathymetry
Chlorophyll-a
RGB
SDB
Chl-a
List of Figures and Tables
Figure 1: Study Areas and Ground-truth data in comparison with VENμS satellite imagery.
Figure 2: SDB results for low and high Chl-a content for the Achziv ridges.
Figure 3: SDB results for the Harbour of Sebastos and the Hader port.
Table 1: Comparison between in situ depth points taken during the Caesarea shipwreck excavation of December
2017 and the SDB map from May 2020.
INTRODUCTION
Most common approaches for deriving bathymetry rely on acoustic systems (such as sonar) or aerial
alternatives such as LiDAR. However, these methods are expensive, labour-intensive and difficult to
scale them into large areas (Stumpf et al. 2003, 547; Traganos et al. 2018, 2). In contrast, in recent
years, Satellite-Derived Bathymetry (SDB) has been suggested as cost-effective for regions where
traditional methods are either impractical to operate or highly expensive (Jagalingam et al. 2015, 565;
Sam et al. 2018, 750), or there is poor or no data at all (Westley 2021, 17). The use of satellites to
derive bathymetric maps has been proven to be not only reliable (Jagalingam et al. 2015, 560-566;
Guzinski et al. 2016, 243-263; Sam et al. 2018, 1-14) but also cheaper in comparison with the
technologies mentioned above (Jagalingam et al. 2015, 561).
Bathymetric mapping highly benefits maritime and underwater archaeologists by facilitating them to
understand site formation processes, shipwreck scours (Caston 1979, 193-204; Quinn 2006, 14191432); reconstruct paleo-landscapes (Westley et al. 2014, 411-430; Westley 2021, 12-14) as well as to
1
�conserve, protect, and preserve underwater cultural heritage (Maarvelend et al. 2013, 191-192). In this
paper, near-shore landscape reconstruction is assessed through SDB and rock identification through
VENµS satellite imagery. The study incorporates a procedural framework encompassing sea
conditions such as low Chl-a content prior to acquiring high-resolution satellite imagery over the area
of interest, and two algorithms capable of identifying rocks above and below the water. The
significance of this approach stems from its replicability in oligotrophic waters of the Pacific Ocean,
as well as the potential utility of the proposed algorithms in coastal environments exhibiting analogous
reflectance properties.
CASE STUDIES
For the application of SDB, two different areas were selected along the coast of Israel. The underwater
aeolian Achziv ridges, located off the coast of the North District (Figure 1A), were chosen due to their
proximity to Shikmona (Haifa), where a 6-year record of Chl-a content is available, and lowbathymetric data is accessible. With respect to important archaeological sites, only Tel Achziv is
known (c. 5 km south of the Israeli border with Lebanon). This site was a Phoenician city that rose at
the end of the 8th century BCE and was also a maritime stop thanks to its convenient seaside location
and easily accessible sand beach for landing (Jasmin et al. 2016, 276).
The second area includes the Roman harbour of Sebastos and the modern port of Hadera (Figure 1A).
The former was chosen because it is a very well-studied harbour (Raban et al. 2009; Bergin 2018;
Galili et al. 2021, 8-16) and in situ depths are available. The latter because it contains low-resolution
bathymetry, which serves as ground-truth data. The harbour of Sebastos, now fully submerged, was
built by King Herod in 21 BCE. It took more than five years to construct, and when completed, it was
the largest artificial harbour of its time in the Mediterranean (Raban 1992). Hadera is a medium-sized
port, located around 3.7 km south of the previous. This port was completed in the early 1960s, and it
currently specialises in coal and fuel oil products and serves the two adjacent power stations
(MarineTraffic 2023; Shipnext 2023).
RESOURCES
The resources available to conduct this work include:
Sonar Data
Sonar bathymetric data was collected between 2001 and 2006. Horizontal resolution is 50x50 m and
one metre vertically. Although this data is highly reliable, its spatial resolution is too broad, and it does
not cover near-shore areas and regions proximate to harbours, which makes it impractical for maritime
archaeology applications.
Chl-a Field Observations
Although there is some research including Chl-a concentrations to produce SDB maps (Li et al. 2019,
4; Li et al. 2021, 4), they do not evaluate how high concentrations can mislead SDB calculations. To
estimate the sensitivity of SDB to fluctuating Chl-a concentrations, a series of measurements were
taken from 2013 – 2019 on a weekly to monthly basis at the Shikmona station (Raveh 2015, 1-23;
Rahav 2018, 10). Two notable contrasting periods were identified: one, during the Israeli summer
season on 25 July 2018 (low Chl-a concentrations), and another on 14 December 2018 (high Chl-a
content).
In-situ Depth Measurements
In December 2017, underwater excavations took place in Caesarea, in the northern part of the bay,
around 60 m offshore (Derenne et al. 2019, 77). The investigation was led by Prof. Emmanuel Nantet
from the University of Haifa. The excavation was aimed at conducting a reappraisal of a shipwreck
discovered in 1976, briefly explored by Avner Raban (2008, 129; 2009, 69-149) and subsequently
2
�studied by Michael Fitzgerald (1989a, 4-9; 1989b, 184-190; 1989c; 1994, 163-223; 1995). Due to the
important dimensions of her hull components, especially the 10-cm thick planking, it seems that she
was initially a large merchantman, that sank in the Early Roman Period (Nantet 2020). Ten hull points
were recorded from the ship, using a Total Station following the technique specified by Bowens
(2009, 92). These points were later used to validate SDB depths in the Habour of Sebastos.
VENμS Satellite Imagery
VENμS (Vegetation and Environment monitoring New Micro-Satellite) is a recent initiative between
the Israeli Space Agency (ISA) and the French Space Agency (CNES) aimed at developing,
manufacturing, and operating a new Earth observing satellite using a superspectral camera that
provides high resolution imagery in both space and time (VENμS, 3). VENμS acquires satellite
imagery at four, five, and 10 m resolution with a revisit period of every two days. VENμS can be
accessed at https://venus.bgu.ac.il/venus/. It provides three levels of products: L1 (TOA reflectance),
L2, and L3 (surface reflectance). Two L3 products for the Achziv ridges were employed, one on 25
July 2018, and another on 14 December 2018 for low and high Chl-a content, respectively. The other
product (L2) was used for the Caesarea and Hadera ports under low Chl-a conditions and was taken on
21 May 2020.
Drone Imagery
Although the harbour of Sebastos was the main commercial maritime trading place during the Roman
and Byzantine periods, natural anchorages were highly utilised as well. The Sebastos harbour complex
has two natural anchorages, which have been thoroughly studied by Ratzlaff et al. (2017), Galili
(2017), and Galili et al. (2021). These two natural anchorages are commonly labelled as Northern and
Southern anchorages. In this area, one set of aerial imagery was collected. The UAV deployed was a
DJI Mavic Mini at 50-m above sea level to qualitatively validate the presence of these anchorages as
well as some other underwater and above-water rocks along the study area. Images were taken on 10
February 2021 before the Israeli oil spill (16 February 2021). The images were then converted into
orthomosaics by using the professional 3D modelling software Agisoft Metashape.
FRAMEWORK
The research questions for this paper are:
ï‚· Which climate and water conditions should be considered to derive bathymetry from satellite
sensors?
ï‚· Up to what depth is satellite-derived bathymetry still reliable along the Israeli coast?
ï‚· What is the reliability of the method in comparison with in-situ measurements?
ï‚· How can one easily highlight both above-water and shallow underwater rocks?
ï‚· How do underwater archaeologists benefit from this?
RESULTS
Except for L1 products, VENμS does not require a long pre-processing stage (e.g., DN to radiance and
radiance to reflectance) or atmospheric corrections. The spectral band ratio model used in this research
is based on Stumpf’s linear algorithm (Equation 1). The algorithm requires tunable constants mo and
m1 to scale the ratio to absolute depth values (Stumpf et al. 2003, 550); n is generally taken as 1000
(Sam et al. 2018, 8; Li et al. 2021, 4; Traganos et al. 2018, 5) to ensure a positive outcome. Bands blue
and green are used due to their maximum penetration capabilities, which correspond to bands two and
four for VENμS. For this research, a variation of Stumpf’s equation was used (Equation 2) as
proposed by Sam et al. (2018, 4) for relative depths where no tunable parameters are needed but
ground-truth data is employed instead.
3
�ln(ð‘›âˆ—ðµ2)
ð‘ = ð‘š0 ln(ð‘›âˆ—ðµ4) − ð‘š1 ….……………………Equation 1
ð‘ð‘Ÿ =
ln(ð‘›âˆ—ðµ2)
….……..…………...….………Equation
ln(ð‘›âˆ—ðµ4)
2
First, Equation 2 is applied in a training area where sonar data near the shore is available (Figures 1B
and 1D). The values obtained from this band ratio underwent a low-filter convolution to smooth and
decrease the disparity between pixel values. Then, all pixel values were converted from five to 50 m
pixel size to match the sonar’s spatial resolution. A scatter plot is produced between sonar (x-axis) and
spectral (y-axis) data, and a quadratic regression model is obtained to ensure the best fitting model
(Figures 1C and 1E).
Second, a new band ratio is applied in a near-shore region of interest, and depth values are derived
from the quadratic model, from which only positive and real values are considered. These values are
assigned to a nx1 matrix labelled as Z. An additional nx2 matrix containing values for latitude (X) and
longitude (Y) (in UTM coordinates) is adjoined to the previous matrix. These points are then exported
to ArcGIS 18.0, and an SDB map is obtained by using kriging interpolation (Amante 2016, 123-133).
Figure 1: Study Areas and Ground-truth data in comparison with VENμS satellite imagery. a) Study Areas; b) Sonar
bathymetry map for the Achziv ridges; c) Scatter plot and regression analysis between sonar bathymetry (x-axis), and
band ratio values (y-axis). For high Chl-a content: Y = 0.00009X2 + 0.00224X + 0.93679. For low Chl-a content, Y = 0.00039X2 + 0.02046X + 0.91304; d) Sonar bathymetry map for the Harbour system of Caesarea; e) Scatter plot and
regression analysis between sonar bathymetry and band ratio values, Y = - 0.0003816X2 + 0.020445X + 0.856941.
SDB Performance under Different Chl-a Concentrations: The Achziv Ridges
Two bathymetric maps were generated for the Achziv ridges, its closeness to Shikmona makes them
ideal for relating Chl-a measurements to specific dates. RGB colour composition is shown for low and
high Chl-a content (Figures 2A and 2B). Maximum depths reach 23 m during July, as shown in Figure
1C, when Chl-a concentrations are likely to be low. In contrast, although the coefficient of
4
�determination (R2 = 0.9784) derived from sonar and spectral values was high during high Chl-a content
(Figure 1C), SDB mapping was demonstrated to be entirely ineffective by not only concealing the
aeolianite ridges but also misleading water depth values (Figure 2D) of up to 62.3-m. Additionally,
white pixels represented erroneous and false bathymetry by showing values up to 12 m above sealevel.
Conversely, SDB for July displays the ridges in detail. A major ridge expanding in a NNE-SSW
direction, and two minor ridges closer to the shore at depths of 6–10 m were visible. Additionally,
SDB proved to be useful for identifying shallow coastal geomorphological features such as a possible
basin at 10–13 m depth, and an isolated rounded feature around the middle of the main ridge (Figure
2C), all of them not visible on the sonar data.
Figure 2. SDB results for low and high Chl-a content for the Achziv ridges; a) low Chl-a RGB; b) high Chl-a RGB; c)
low Chl-a SDB, two features; d) high Chl-a SDB, pixels in white denote false bathymetry above mean sea level.
SDB and Rock Identification: The Harbour of Sebastos and the Hadera port
The previous methodology was followed for the second study area (Figure 3A), obtaining a point grid
matrix of nx3, containing latitude, longitude, and depths derived from the quadratic equation (Figure
1E), from which a high-resolution (five m/pixel) georeferenced bathymetric map was generated,
covering a total area of 15,770 km2 (Figure 3B). Shallow areas were found between Hadera port and
Sebastos harbour. Within these regions, traditional ship-based measurements would be almost
inaccessible due to high expenses and complicated logistics in comparison with SDB. The algorithm’s
final limitation went up to 23 m (Figure 1E), similar to the Achziv ridges (Figure 2).
In general, SDB has better performance between four and ten metres deep. Uncertainties appear below
four metres deep because the water column attenuation becomes very weak due to the short light
transfer path (Dekker et al. 2011, 405, 415; Li et al. 2019, 11), which can lead to small discrepancies
between the blue (band two) and green (band three). Moreover, the reflective properties of bottom
substrates and bottom albedo also affect its accuracy (Green et al. 2000, 220-233). Above 10 m, light
is attenuated, which can lead to weak signals (Lee et al. 2012, 2578).
To evaluate the SDB’s performance, satellite depths were compared with the data mentioned in the
Resources Section. Comparison between these measurements taken in situ and SDB depths (Figure
3C) yielded an outstanding RMSE of 0.52 m (Table 1), which is remarkably good if compared with
similar studies (Westley 2021, 8), where the best RMSE was 2.56 m using Sentinel 2 data (10 m/pixel)
and a polynomial fitting, or Li et al. (2019, 8), who reported an RMSE of 1.67 m using Planet Dove
5
�satellites (four m/pixel). Note that the shipwreck was again covered by sand during the SDB approach;
thus, satellite depths should be slightly larger to reach the hull.
Concerning rock identification, it was found that due to their water penetration capabilities, by
multiplying bands three (cyan) and four (green), submerged rocks in shallow waters were enhanced.
Likewise, rocks above the water were identified by subtracting band eight (red edge) from band seven
(red). The results of applying both algorithms for rock identification are integrated in Figure 3.
Underwater rocks are displayed in red, while rocks above the water are shown in yellow. Validation of
the proposed algorithms for identifying rocks above and below the water was qualitatively
corroborated in Figure 3D by overlying drone imagery over the rocky areas.
Figure 3. SDB results for the Harbour of Sebastos and the Hader port a) RGB; b) SDB map and rock identification
map; c) location of the Caesarea shipwreck points; d) location and validation of the Northern anchorages; Southern
anchorages are enclosed in the white box.
Table 1: Comparison between in situ depth points taken during the Caesarea shipwreck excavation of December 2017
and the SDB map from May 2020.
Measurement
number
Measured depths in situ
(m)
SDB depths
(m)
Depth Difference
(m)
1
2
2.5441
2.5771
3.021
3.021
0.4769
0.4439
3
2.7984
3.021
0.2226
4
2.6654
3.139
0.4736
5
2.5230
3.139
0.716
6
2.8519
3.139
0.2871
7
2.8090
3.118
0.309
8
2.5481
3.118
0.5699
9
2.1775
3.139
0.9615
10
2.7698
3.118
0.3482
RMSE = 0.5253 m
6
�CONCLUSIONS
The results can be used to comprehend the geological and archaeological landscape of the ancient
harbour of Sebastos as well as the northern ridges of Achziv. This approach can be easily replicated in
other regions as long as Chl-a concentrations remain low using any other multispectral set of imagery
(preferably high resolution). The following conclusions can be drawn from this research:
ï‚·
ï‚·
ï‚·
ï‚·
ï‚·
ï‚·
ï‚·
For the Israeli coast, SDB mapping should be done for images taken between March and
September, when Chl-a concentrations are likely lower.
Results show that a high R2 coefficient between ground-truth and spectral data does not
necessarily mean that SDB values will be accurate or trustworthy; hence, special attention
should be given to the environmental conditions at the time of image acquisition.
Both VENμS products (L3 and L2) yielded highly reliable results and are highly
recommended for SDB bathymetry studies.
The maximum light penetration depth for the coast of Israel was up to 23 m. Errors likely
below this depth.
The product obtained from multiplying bands three and four from VENμS can be used for
identifying rocks submerged in shallow waters.
The subtraction of band eight from band seven is suitable for detecting rocks above the
water level.
It is strongly recommended to integrate rock identification with SDB for future research
projects.
It will be of special interest to replicate this method in the Asian Pacific to test both light penetration
capabilities and the ideal yearly timing for multispectral image acquisition based on the Chl-a content
of a proposed study area. Likewise, rock detection using other sensors should be examined as well.
ACKNOWLEDGMENTS
This research would not have been possible without the support from the University of Haifa scholarships during my M.A.
programme.
7
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9
�
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2023 Session 21: New Technologies and Interdisciplinary Strategies for the Promotion and Protection of Maritime Cultural Heritage
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Papers presented at Session 21 of the 2023 Asia Pacific Regional Conference on Underwater Cultural Heritage
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Satellite-derived bathymetry and rock detection for maritime archaeology using VENµS imagery
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Since its beginnings in 1975, deriving bathymetry by means of multispectral satellite imagery has been a method
that has not yet been fully exploited in the maritime archaeology realm. It focuses on using the blue and green
bands for their water penetration capabilities to later convert each pixel into depth values. This method can be
replicated in time and space, while keeping costs low and covering large areas. In this research, two highresolution bathymetric maps using VENµS satellite imagery and a variation of Stumpf’s equation were
produced. Two archaeological sites were selected: the harbour of Sebastos (built by King Herod) and the Achziv
ridges on the northern coast of Israel. The importance of collecting satellite imagery under low Chl-a [mg/m3]
conditions is addressed, and an algorithm for identifying shallow rocks above and below the water level is
included. Our research suggests that satellite-derived bathymetry mapping along the Israeli coast is more
efficient for satellite images taken between March and September, when Chl-a concentrations are likely to be
lower; maximum depth penetration using VENμS is found to be approximately up to 23 m depth with a Root
Mean Square Error (RMSE) of 0.53.
Creator
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Gerardo Diaz
Yoav Lehahn
Emmanuel Nantet
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The Museum of Underwater Archaeology
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2023
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English
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A bibliographic reference for the resource. Recommended practice is to include sufficient bibliographic detail to identify the resource as unambiguously as possible.
Diaz, Gerardo. 2023. “Satellite-derived bathymetry and rock detection for maritime archaeology using VENµS imagery.” Edited by Jennifer Craig, Jay Mok, T. Kurlt Knoerl, and Hans van Tilburg. In Proceedings of Fifth Asia Pacific Regional Conference on Underwater Cultural Heritage: Gwangju, The Republic of Korea, November 13-18 2023. The Museum of Underwater Archaeology. URL: https://apconf.omeka.net/exhibits/show/apconfproceedings/item/1914
Asia-Pac Session 21 2023
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https://apconf-much.org/proceedings/files/original/7062be1e10a33b21a436fa48583d28f0.pdf
d7b554f1ee475142c7c78319a9bf60ff
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The Application of Photogrammetry for Recording Indonesian Vernacular and Historical
Boats and Boat Miniatures in Museum Collections
Ahmad Ginanjar Purnawibawa1,2 Chiara Zazzaro1 Agni Mochtar1,3
1
Università di Napoli “L’Orientale”, Italy
Universitas Pendidikan Ganesha, Indonesia
3
National Research and Innovation Agency (BRIN), Indonesia
2
ABSTRACT
This paper fits best within Session 27 New Technology and Interdisciplinary Strategies as it focuses on the status and
preservation of vernacular and historical boats and boat miniatures within Indonesian museum collections. The case
study under consideration concerns challenges and strategies of using photogrammetry for recording these museum
collections and for preservation, dissemination, and scientific research. The resources available to conduct the work
include the full-size and miniature Indonesian boats kept in the Museum Nasional and Kebaharian Museum in
Jakarta and other collections in Indonesia. The research questions of this project are: what is the suitable method, and
what are the challenges in the 3D documentation of full-sized boats and miniatures in museums using the
photogrammetry technique? The results of this project are comprehensive data regarding the photogrammetry
workflow for museum collections and sets of digital boat models suitable for disseminating information and for
scientific publication. This project is part of the Indonesian Boatbuilding Endangered Heritage Project, an ongoing
collaboration among Indonesian and Italian scholars.
Keywords: boats, miniatures, museum collections, photogrammetry
List of Figures and Tables
Figure 1: The comparison of photos sequences between miniature and full-sized boats. Reconstruction on Agisoft
Metashape by C. Zazzaro, 2023.
Figure 2: Detailed result on miniature boat Janggolan Madura. Reconstruction on Agisoft Metashape by C. Zazzaro,
2023.
Figure 3: Defects on models shown on two sides of the boats. Reconstruction on Agisoft Metashape by C. Zazzaro,
2023.
Figure 4: Imperfections due to reflection on sail material. Reconstruction on Agisoft Metashape by C. Zazzaro, 2023.
INTRODUCTION
In the last decades, the application of photogrammetry in the cultural heritage field has dramatically
increased. Photogrammetry is easily accessible to everyone, and it provides a permanent record of heritage
materials and data for accurate measurement and analysis (Yilmaz, Yakar, and Yildiz 2008, 9), which
benefit the documentation and reconstruction process, and research dissemination (Forlin, Valente, and
Kázmér 2018, 2). The digital data recorded by this method benefit researchers from different fields,
including archaeologists, who can better manage the time spent on the field (Puspita et al. 2021, 343). For
Indonesian museums, photogrammetry has become more popular with the rise of demands for digital
access to museum collections. The need for digital access to entertainment and education spiked,
especially during the COVID-19 pandemic (Bramantyo and Ismail 2021, 185; Soraya and Sigit
Martyastiadi 2021, 26). However, only a few museums can cope with the demands, and most collections
still need to be digitally represented nowadays—especially endangered maritime heritage in the form of
historical and vernacular boats. In fact, in nautical archaeology, photogrammetry is especially useful for
reverse engineering processes, extrapolating naval lines from 3D models and creating a permanent record
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�of boat architectures. Unlike other types of applications, photogrammetry measurements and tolerances
are much less restrictive, and the accuracy obtained is sufficient at this scope (Martorelli, Pensa, and
Speranza 2014).
Vernacular boats and boatbuilding in many places in Indonesia faced a rapid decline with the introduction
of modern shipbuilding, accompanied by a high demand for manufactured ships. The lack of knowledge
transfer within the boatbuilder communities exacerbates the decline. As observed in the boatyards in
Pasuruan, East Java, the skills and knowledge of boatbuilding are only taught from fathers to sons, without
any guarantee that today’s generation wants to continue working on building boats (Mochtar, Taniardi and
Purnawibawa 2021). A similar situation is found in Tana Beru, a village in South Sulawesi, where there is
probably the largest cluster of wooden boatyards in the world, especially for building a type of boat
known as pinisi. Here, most of the production concerns large boats, and only a few builders master the
skills to make boats using traditional tools and processes and with the mandatory accompanying
ceremonies (Zazzaro et al. 2022).
The Endangered Indonesian Boat Building Heritage Project focuses on documenting the endangered
boatbuilding traditions in Indonesia while also building up a digital archive of boats and boat miniatures
collections, which are often overlooked. The digital copy of these collections could be used as educational
tools and for conservation purposes. This latter use, for example, would have helped preserve boats of the
Jakarta Maritime Museum, which lost around 100 collection items to a fire in 2018, including a Balinese
outrigger boat and other important vernacular and historical boats (Nizar 2018). While the museum has
now finished its reconstruction and is operating normally, the loss of part of the collection is severe. Even
though digital archives will not replace the actual collections, their absence prevents the museum from
creating replicas or integrating the exhibit with the digital collection. The Endangered Indonesian Boat
Building Heritage Project campaigns to avoid a similar scenario from happening again using
photogrammetry for documenting the boats and boat miniatures collections.
CASE STUDIES
The case study under consideration concerns challenges and strategies of using photogrammetry for
recording historical and vernacular boats and boat miniatures in museum collections and for preservation,
dissemination, and scientific publication. In the form of boats and their depiction, the maritime heritage is
critically underrepresented in virtual platforms. The only present collections are the pinisi boat and
the janggolan boat. Both miniatures are collections of the National Museum and are featured in the
National Museum virtual tour (Virtual Tour 2023). Another boat type is the alut pasak dayak, a full-sized
boat from the Jakarta Maritime Museum collection featured in the Tetangga Exhibition web-based online
platform (Tetangga Exhibition 2023). Usually, the museum works together with third parties to provide all
models used in these virtual or online exhibitions. The lack of proper equipment and necessary skills is
mentioned as the cause of the museum's inability to support its own need for a virtual museum. Hence,
there is a need to address this issue.
Despite some ambiguous information on the provenance of some boats and boat models, every object has
been carefully documented, just like an archaeological artefact. The recording is performed with a nautical
archaeology approach, meaning that the documentation attempts to record all details in the object in
opposition to merely recording the general form. Besides 3D photogrammetry of the boats and boat
models, the project also aims to produce more detailed information, such as the hull lines and the
description of the boat's components. Therefore, the results of this project would be helpful for the general
public who only wish to see the collection and the specific public, such as researchers and conservators,
who need to observe the detail of the objects. Another aim of the project is to train museum conservators
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�in photogrammetry documentation so that they will systematically produce digital copies of the new
collection acquisitions in the future.
RESOURCES
The boats and boat miniatures recorded in this research are collections of various museums in Indonesia,
namely the National Museum of Indonesia, Jakarta Maritime Museum, Museum of Indonesia, and
Transportation Museum. The chosen boats and miniatures represent different regions in Indonesia and
represent traditional workmanship for actual-sized boats, while the miniatures, to some degree, provide
accuracy and similarities to the actual boats they represent. Miniature boats are usually made by artisans
who know the boats' architecture very well because they usually live in the area or they were former
boatbuilders.
So far, data have been gathered from 2019 to 2023 through a series of fieldwork by research members.
The documentation processes are conducted using different mirrorless digital cameras, Sony RX 100II,
Sony Alpha 7C, Canon M100, and Canon M50. In order to reconstruct the objects using the
photogrammetry technique, this research uses the program Agisoft Metashape. To support the purpose of
disseminating the project results, Sketchfab is chosen as an online platform. Sketchfab offers dedicated
categories for cultural heritage and historical objects and has been used by institutions as well as amateurs
to display their collections. Sketchfab also provides editing tools and supports virtual reality devices
(Statham 2019).
FRAMEWORK
Considering the urgency of photogrammetry documentation and its benefits for the public and scientific
field, there is a need for rapidly, yet properly, documenting the collection of boats in Indonesian museums.
This article explores the suitable method and challenges in documenting full-sized boats and miniature
boats in museums using photogrammetry.
RESULTS
Photogrammetry Processes
The principle of photogrammetry is to reconstruct the three-dimensional form of an object in digital form
through a series of photographs. Ideally, the photographs cover 360 degree angles of the object from
different elevations. Considering the complicated shape of the boats, the photos easily surpassed hundreds
to generate desirable results. There are several steps to execute the work efficiently in a photogrammetry
workflow. The basic workflow includes the digitization processes, which can be broken down into several
steps, including preparations, recording, pre-processing, measurement analysis, finishing, exporting
(Puspita et al. 2021, 344), and continued with interpretation and visualization processes to make the
models accessible through different means (Condorelli and Bonetto 2022).
Following those steps should help us to produce optimal results for photogrammetry. However, the shape
of the objects, space, and light limitations inside the museum challenged the workflow. Most of the fullsized boats in the museums cannot be moved from the display room due to their weight and space
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�limitations inside the museum. For example, the Papua Canoe kept in the Jakarta Maritime Museum is
'trapped' by the museum building's structural pillars due to its large size. Another challenge was the
lighting conditions in the museum: some 'immovable' collections are hard to be photographed with even
lighting due to their positions and the proximity to structural obstacles such as walls and pillars, which
also create shadows. Finally, the museum's lighting level, which was kept dim between 50-100 lux,
proved challenging to work with. Digitisation proceeded in such conditions and limitations.
The first step was the selection of the full-sized boats based on their authenticity, historical information
provided by the museum, and visual observation in the museum. Only historical and vernacular boats were
documented, and modern boats were excluded since they did not provide value to this project. Otherwise
the miniature boats were selected based on their accuracy in representing the actual boat type, museum
information, team observation, and craftsmanship. Miniatures of modern boats and 'strange-looking'
vernacular boats deemed proportionally or architecturally inaccurate, were excluded. The project recorded
two full-sized / eight miniature boats at the National Museum, eight full-sized / five miniature boats at
Jakarta Maritime Museum, four full-sized / four miniature boats at the Transportation Museum, and two
miniature boats at the Museum of Indonesia.
The next step was recording or taking photographs of the boats. Miniature boats were more manageable
compared to full-sized boats due to their size. They were usually displayed in a glass vitrine which can be
easily transported to more open areas and placed on top of a table or pedestal helpful for the
photogrammetry workflow. In order to document the miniatures, the object was photographed from all
directions or 360 degrees with different elevations to capture details. For example, the higher elevation
angles captured the mast, sail, and deck, and the lower angles captured the hull, keel, and rudder. A
detailed photograph can be obtained while maintaining adequate overlap pictures capturing the whole
dimension of the miniature boats.
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�Figure 1: The comparison of photos sequences between miniature and full-sized boats. Reconstruction on Agisoft
Metashape by C. Zazzaro 2023.
On the other hand, recording a full-sized boat in museum collections requires a different approach. Space
and light limitations and the size of the boat made shooting more complicated. A full-sized boat cannot be
treated as a single object due to its size and obstacle in the working area. The team documented parts of
the boats individually, and then tried to connect to these parts digitally. The focus of the documentation is
on parts that contain essential detail. Since it was almost impossible to photograph the complete shape of
the boat, continuity and overlap from one photo to the next were essential. With this approach, photos
taken on full-sized boats have a clear direction and retain detail from all parts of the boat. The
consequence of this technique was that the number of pictures taken was greater than the photos in the
miniature collection, as shown in Figure 1. This process was also directly followed by museum staff, who
participated in documenting their collection.
Photos from each boat collection were then archived digitally, then processed using Agisoft Metashape
software to produce a three-dimensional model. The processing included aligning the photos, building a
dense cloud, building a mesh, texturing, calibrating, and simplifying the mesh for smaller file-size models.
The final result was then exported in .obj and .mtl format, and texture map files were uploaded to
Sketchfab.
Photogrammetry Results
The results of this project provided us with various data sets of historical and vernacular boats and
miniatures in the form of three-dimensional models and detailed pictures. The photogrammetry method
yielded satisfactory results, with the three-dimensional models successfully preserving the detail and
texture of the boat and miniature boats, as shown in Figure 2. The detail allowed us to access more data
for future research, including the iconography of the boats, decoration, and pattern used by different
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�vernacular boats. The calibrated model also preserved the detailed measurement of the boat parts. This
record will provide invaluable data for studying boat characteristics, reverse engineering, and
understanding the nature of the boats, especially in full-sized boats.
Figure 2: Detailed result on miniature boat Janggolan Madura. Reconstruction on Agisoft Metashape by C. Zazzaro 2023.
However, on a few models, there are defects in the final results due to imperfections in capturing the
image of the boat. Three factors usually contribute to the quality of the model produced from the
photogrammetry: image quality, scene complexity, and environmental condition (O'Connor 2018). In this
project, two noticeable imperfections can be observed in the final models: the different coloration of the
boat parts and the holes usually in the lower parts of the boat models.
The difference in coloration (as shown in Figure 3) could be observed in two different parts of the models
due to the difference in light exposure. Figure 3 shows that the A side of the boat is correctly exposed to
the light, while the B side is underexposed. Figure 3 shows that if the image records a shadow, the shadow
will also be introduced to the final models (Kreimer 2020). This defect is often shown on full-sized boats,
especially those positioned in the limited space of display rooms, which prohibit the introduction of
additional lights or a tripod for long-exposure photographs. This defect could be reversed using Agisoft
Delighter, with the expense of losing texture and detail on the model's surface, which is not ideal for the
purpose of this project.
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�Figure 3: Defects on models shown on two sides of the boats. Reconstruction on Agisoft Metashape by C. Zazzaro 2023.
Another visible defect is the presence of holes in less textured and plain materials. In this case, holes
occurred in the sail of miniature boats (see Figure 4). Single-colored materials lacking physical texture are
difficult to reconstruct in photogrammetry (Kreimer 2020, 7). However, Figure 4 shows that Model A
preserves the sail's detail and shape much better due to exposure to adequate light than Model B. The
underexposed Model B also shows the cast of shadows in several parts, including the sail, mast, deck, and
hull. While this defect is less likely to impact measurement data and its potential for scientific purposes
(except the study of iconography, which is affected by the loss of details due to shadows), these models
are less desirable to use for public benefit, considering their appearance.
Figure 4: Imperfections due to reflection on sail material. Reconstruction on Agisoft Metashape by C. Zazzaro 2023.
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�The photogrammetry results from this project show that practical methods for documenting the objects
needs to be adapted to the complexity of the objects. The shape and size of full-sized boats provide
challenges for the documentation team, which need to be overcome with a slightly different approach
from the usual photogrammetry method. This project also shows the importance of proper lighting and
location setup for object documentation. Considering the high complexity of the vernacular boats and
miniatures, the details need to be preserved properly to allow their digital copies to benefit scientists and
the public. In the case of Indonesian museums, these challenges are relatively common in many museums
since only a handful of museums are equipped with proper working areas and needed equipment. This
condition could change our mindset for displaying collections or storing collections, especially full-sized
boats, in a more proper location, with access from multiple angles.
CONCLUSION
The results obtained from this project show that the photogrammetric method is an effective method for
making three-dimensional collections models and has succeeded in giving a satisfactory output. However,
due to technical challenges, planning and strategy are needed in collecting data for each collection. The
technical challenges found were the position of the collection in the exhibition space or display room. In
some cases the display space could be more conducive to photogrammetry by removing obstruction of
building structures, and more space to place the camera. Another challenge is ensuring enough light in the
photograph process. The position of the collection and the lighting conditions often make the collection
underexposed, or in some cases, cause the material in the collection to reflect light, which makes the 3D
model imperfect.
For this reason, a different approach is needed to record the different types of collections in the form of
full-sized boats and miniature boats. Documentation of full-sized boats can be done in several sections and
focuses on boat attributes, compared to miniature boats that can be documented as whole objects. As a
result, a three-dimensional model can be obtained with accuracy and detail and can be used for
educational, academic, and public purposes.
ACKNOWLEDGEMENT
We thank the Italian Ministry of Foreign Affairs and the International Association for Mediterranean and Oriental Studies
(ISMEO) for supporting the Indonesian Boatbuilding Endangered Heritage Project. We are also thankful to the Museum Nasional
Indonesia (Indonesia National Museum), Museum Kebaharian Jakarta (Jakarta Maritime Museum), Museum Indonesia (Museum
of Indonesia), and Museum Transportasi (Transportation Museum) for providing access needed for the documentation of the
museum collections.
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�BIBLIOGRAPHY
Bramantyo, B. D., and P. Ismail. “Digital Tourism Museum Nasional Indonesia Melalui Virtual Tour Di Masa Pandemi COVID19.” WACANA: Jurnal Ilmiah Ilmu Komunikasi 20, no. 2 (2021): 184–196. https://doi.org/10.32509/wacana.v20i2.1616.
Condorelli, F., and J. Bonetto. “3D Digitalization and Visualization of Archaeological Artifacts with the Use of Photogrammetry
and Virtual Reality System.” In International Archives of the Photogrammetry, Remote Sensing and Spatial Information
Sciences - ISPRS Archives, 48 (2022): 51–57. International Society for Photogrammetry and Remote Sensing.
https://doi.org/10.5194/isprs-archives-XLVIII-2-W1-2022-51-2022.
Forlin, P., R. Valente, and M. Kázmér. “Assessing Earthquake Effects on Archaeological Sites Using Photogrammetry and 3D
Model Analysis.” Digital Applications in Archaeology and Cultural Heritage 9, no. 6 (2018): 1-14.
https://doi.org/10.1016/j.daach.2018.e00073.
Kreimer, B. “Guide to Photogrammetry Photography.” Washington, D.C: Online News Association, 2020.
Martorelli, M., C. Pensa, and D. Speranza. “Digital Photogrammetry for Documentation of Maritime Heritage.” Journal of
Maritime Archaeology 9, no. 1 (2014): 81–93. https://doi.org/10.1007/s11457-014-9124-x.
Mochtar, A., P. Taniardi, and A. G. Purnawibawa. “As my father said Traditional boatbuilding in Pasuruan.” The SEAMEO
SPAFA International Conference on Southeast Asian Archaeology and Fine Arts, December, (2021): 234–240.
Nizar, H. Interview on JPNN, 17 January 2018. https://www.jpnn.com/news/kerugian-akibat-kebakaran-museum-bahari-takternilai, accessed 19 April 2023.
Puspita, A. A., M. Triharini, M. Risfan, and B. Salam. “A Study on Museum Artifact Digitization Using Photogrammetry Method
for Preservation and Design Education.” Advances in Social Sciences, Education and Humanities Research 65 (2021): 343350. https://doi.org/10.2991/assehr.k.211228.045.
Soraya, A., and Y. Sigit Martyastiadi. “Aesthetics of Virtual: The Development Opportunities of Virtual Museums in Indonesia.”
International Journal of Creative And Arts Studies 8 no. 1 (2021): 25-33. https://doi.org/10.24821/ijcas.v8i1.5346.
Statham, N. “Scientific Rigour of Online Platforms for 3D Visualisation of Heritage.” Virtual Archaeology Review 10, 20 (2019):
1–16. https://doi.org/10.4995/var.2019.9715.
Tetangga Exhibition. Jakarta Maritime Museum. https://tetanggaexhibition.com/en/node/3, accessed 19 April 2023.
Virtual Tour. Badan Layanan Umum Museum Nasional Indonesia. https://www.museumnasional.or.id/virtual-tour, accessed 19
April 2023.
Yilmaz, H. M., M. Yakar, and F. Yildiz. “Documentation of Historical Caravansaries by Digital Close Range Photogrammetry.”
Automation in Construction 17, 4 (2008): 1–10. https://doi.org/10.1016/j.autcon.2007.09.003.
Zazzaro, C., H. Liebner, A. Soriente, G. Ferraioli, and A. G. Purnawibawa. “The Construction of an Historical Boat in South
Sulawesi (Indonesia): The Padewakang.” Journal of Maritime Archaeology 17, 4 (2022): 507–557.
https://doi.org/10.1007/s11457-022-09332-5.
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2023 Session 21: New Technologies and Interdisciplinary Strategies for the Promotion and Protection of Maritime Cultural Heritage
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Papers presented at Session 21 of the 2023 Asia Pacific Regional Conference on Underwater Cultural Heritage
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Asia Pacific Regional Conference on Underwater Cultural Heritage
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The Application of Photogrammetry for Recording Indonesian Vernacular and Historical Boats and Boat Miniatures in Museum Collections
Description
An account of the resource
This paper fits best within Session 27 New Technology and Interdisciplinary Strategies as it focuses on the status and
preservation of vernacular and historical boats and boat miniatures within Indonesian museum collections. The case
study under consideration concerns challenges and strategies of using photogrammetry for recording these museum
collections and for preservation, dissemination, and scientific research. The resources available to conduct the work
include the full-size and miniature Indonesian boats kept in the Museum Nasional and Kebaharian Museum in
Jakarta and other collections in Indonesia. The research questions of this project are: what is the suitable method, and
what are the challenges in the 3D documentation of full-sized boats and miniatures in museums using the
photogrammetry technique? The results of this project are comprehensive data regarding the photogrammetry
workflow for museum collections and sets of digital boat models suitable for disseminating information and for
scientific publication. This project is part of the Indonesian Boatbuilding Endangered Heritage Project, an ongoing
collaboration among Indonesian and Italian scholars.
Creator
An entity primarily responsible for making the resource
Ahmad Ginanjar Purnawibawa
Chiara Zazzaro
Agni Mochtar
Publisher
An entity responsible for making the resource available
The Museum of Underwater Archaeology
Date
A point or period of time associated with an event in the lifecycle of the resource
2023
Language
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English
Bibliographic Citation
A bibliographic reference for the resource. Recommended practice is to include sufficient bibliographic detail to identify the resource as unambiguously as possible.
Purnawibawa, Ahmad Ginanjar, Chiara Zazzaro, and Agni Mochtar. 2023. “The application of photogrammetry for recording Indonesian vernacular and historical boats and boat miniatures in museum collections.” Edited by Jennifer Craig, Jay Mok, T. Kurt Knoerl, and Hans van Tilburg. In Proceedings of Fifth Asia Pacific Regional Conference on Underwater Cultural Heritage: Gwangju, The Republic of Korea, November 13-18 2023. The Museum of Underwater Archaeology. URL: https://apconf.omeka.net/exhibits/show/apconfproceedings/item/1915
Asia-Pac Session 21 2023
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https://apconf-much.org/proceedings/files/original/8d87d78d46c3dca6c0a564b0ba97b372.pdf
4201c17d4aab2a18c96a9a725fb4b32e
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The Potential of Maritime Archaeology (Shipwreck Sites) for Sustainable Marine
Tourism Management and Strengthening Historical Narrations in Tidore, North
Moluccas, Indonesia
Wisnu A. Gemilang1
Nia N. H. Ridwan1
Guntur A. Rahmawan1
Ulung J. Wisha2
1
Research Institute for Coastal Resources and Vulnerability, Ministry of Marine Affairs and
Fisheries
Jl. Raya Padang-Painan Km. 16, Bungus, Padang, West Sumatera, 25245
2
National Research and Innovation Agency
ABSTRACT
The potential of shipwreck site resources in “Spice Routes,” Ternate-Tidore, reflects several historical pieces of
evidence relating to archaeological remains from the Portuguese and Spanish eras in the surrounding sea and
coastal areas. In the 1990s, a plethora of archaeological remains were salvaged. An integrated archaeological
study is an initial step to optimize the use of underwater archaeological resources in the area of interest. The
survey consisted of local coordination, expert consultation, literature study, field surveys and underwater
observations, mini excavations using water dredging, artefact samplings site measuring and documentation,
artefact desalination, and C14 carbon dating analysis for wooden materials found within the site. Moreover, the
water quality survey for marine tourism interests and Trinidad ship reconstruction is significant in supporting
500 years of circumnavigation of the earth by Ferdinand Magellan and Juan Sebastian Elcano and supporting
publication and dissemination. Based on the present study, it is observed that Soasio and Tongowai sites have
the potential to be developed as the centre of integrated marine ecotourism with maritime archaeology-based
sites. This consideration is due to plenty of historical artefacts and tourism feasibility assessments. Therefore,
local and regional regulations relating to regional spatial planning are crucial before implementing the
ecotourism project in this area.
Keywords: Maritime archaeology, shipwreck sites, sustainable marine tourism, Tidore
List of Figures and Tables
Figure 1: The distribution of underwater archaeology sites in Tidore Islands. Source: Field survey, Research
Institute for Coastal Resources and Vulnerability, 2021.
Figure 2: The distribution map of historical sites in Tidore Islands.
Figure 3: Documentation of UCH in Tidore Islands; shipwreck indication (a); ceramic findings (b); jars and
earthenware findings (c); bird’s eye view of Soasio site (d).
Figure 4: Biodiversity in the surrounding Soasio site; coral covers (a); fish ecosystem (b), sediment substrate (c).
Figure 5: Documentation of UCH in Tidore Islands; underwater cannon finding (a); excavated cannon from
Tongowai site (b); A pile of earthenware (c); coral covers and ecosystem in Tongowai site (d).
Table 1: The formulation of the underwater heritage trail development strategy.
1
�INTRODUCTION
Tourism is an essential aspect for a country, which can increase state and local government revenue
(Runtunuwu 2020, 1). Tidore Island is becoming the preferred ecotourism destinations in North
Maluku Province. Exotic natural panoramas combined with cultural-historical sites create an
enchanting paradise in eastern Indonesia (Wijayanti et al. 2022, 1). Tidore Island is worthy of further
development due to its strategic position and many mesmerizing coastal areas as a potency for
supporting marine tourism. However, in developing the tourism potency of this region, many aspects
should be considered since there many existing problems (Kader 2017, 20), such as the local facility
and the low awareness of the underwater cultural heritage UCH importance (Fahri & Alhadar 2022, 2;
Runtunuwu 2020, 2).
The existence of two underwater archaeological sites, Soasio and Tongowai Sites, highlight the
potential for underwater archaeology in the Tidore Islands. Aside from high biodiversity within the
sites, these two primary sites have a historical value related to the shipping and international trade in
the 15-17 centuries AD (Rahmawan et al. 2021, 173). Therefore, the further development should be
supported by a tourism development strategy. Local tourism management and third party’s authorities
should contribute to conserve the remains by establishing policies and protections (Masberg and
Morales 1999, 290). Therefore, this research article on "The Potential of Maritime Archaeology
(Shipwreck Sites) for Sustainable Marine Tourism Management and Strengthening Historical
Narrations in Tidore, North Moluccas, Indonesia" is significant to support the development of
underwater historical tourism in the Tidore Islands.
CASE STUDY
Based on information from the local community and local government in Ternate and Tidore, around
the 1990s, there was a lot of goods looting in several archaeological sites in Tidore waters. The lack of
knowledge of the local government and the community about the existence of UCH makes the remains
more vulnerable and less protected (Rahmawan et al. 2021, 170). Therefore, identification of
underwater archaeological potential in Tidore waters is essential as a basis for further conservation,
development, and decision-making in terms of protecting the underwater archaeological remains. In
addition, this study is expected to promote the potential of the site for marine tourism and other
preservation strategies in dealing with the vulnerability of the site and its aquatic environment.
RESOURCES
As mentioned earlier, the primary location of this study is in the Soasio and Tongowai sites, Tidore
Island, North Maluku Province (Figure 1). Many historical objects have been managed as an attraction
for supporting the tourism aspect, such as the Tidore Sultanate Palace, Torre Fort, Tahula Fort,
Sonyine Malige Museum, Sultan Nuku Tomb, Sultan Mosque and Sultan Pier (Sosmiarti and Fahlefi
2019, 282). However, the Tidore Islands underwater history is less promoted and even rarely visited
due to the lack of local awareness regarding the importance of UCH. Therefore, in this study we will
exhibit the underwater archaeological resources in Tidore and further development planning to
promote and manage the remains.
2
�Figure 1. The distribution of underwater archaeology sites in Tidore Islands.
Source: Field survey, Research Institute for Coastal Resources and Vulnerability, 2021.
FRAMEWORK
The primary data of this study were obtained from a research report by the Research Institute for
Coastal Resources and Vulnerability (RICRV) in 2019 and 2021. The research activities included:
mapping bathymetry, hydro-oceanography, geology, and diving to observe archaeological sites' photos
and videos, and the quality of the ecosystem and aquatic environment (Irani et al. 2022, 3). In addition,
local interviews with the government, village officials, and communities around the site were also
carried out.
Masberg and Morales (1999, 290) suggest that five factors are included in ecotourism development:
(1) an integrated approach; (2) planning and a slow start; (3) Education and Training; (4) maximizing
local benefits and (5) evaluation and feedback. Outcomes are for a successful and viable ecotourism
development; these five factors ensure the objectives are achieved.
Artefact data analysis identified UCH from the Soasio Site and the Tongowai Site (Figure 1). We
aimed to determine artefacts type, age, and the place of origin of production. In addition, observations
of the position of the sites and GPS tracking data of important historical sites along the coast near the
Soasio and Tongowai sites were also carried out, which were analysed to know the spatial distribution
in relation to the two sites.
3
�RESULTS
Historical Tourism and Underwater Archaeological Sites in Tidore Islands
The oceanography of the Soasio site is characterized by relatively weak currents so divers can dive
anytime. Aside from the underwater archaeological remains, clear seawater with various types of coral
reefs and fish are attractions. The Soasio seabed has a slope of about 130 degrees. The distribution of
artefacts in ship wood, ballast stone, and ceramics is 15-20 m deep (Rahmawan et al. 2021, 175).
Figure 2: The distribution map of historical sites in Tidore Islands.
Another site is situated in Tongowai Village where the cannon was found at a depth of 37-42 m
(Figure 2). According to local interviews, the cannon had previously been lifted along with other
artefacts by a salvage company in 1998. This was done by Japanese investors, as proved by the
existence of two drums and ropes tied to the cannon, which were used to lift the cannon. The artefacts
discovered in 1998 are stored in a Central Halmahera Guesthouse in Itagapura. The lifting of the
artefacts at the Tongowai Site occurred when Tidore Islands was under the Halmahera Tengah
Regency.
The Significance of Underwater Archaeology in Tidore Islands
Underwater Archaeology in Soasio
The presence of shipwrecks at the Soasio site was known based on findings of four meters of wood in
an inclined position at the depth of 12 meters. The remains are mostly covered by coral reefs and
sediment deposits (Figure 3a). According to the historical records and local interviews, only Spain and
4
�Portugal colonized Tidore Island. Therefore, initial suspicions were that the ship was a Spanish or
Portuguese ship anchored in the port of Tidore. However, the results of the C14 analysis show the
oldest wood sample is from 1054 AD, and the youngest is from 1379 AD.
The ceramics found at the Soasio site are categorized as porcelain and stoneware. Ceramics made from
porcelain have a white glaze and blue-white colour under the glaze. One intact plate is known as
Swatow blue and white porcelain, which was produced during the Wanli period (1575 – 1659 AD) of
the Ming Dynasty (1368-1644 AD), and a bowl fragment is known as blue-white porcelain from the
time of Emperor Tianqi (1621 – 1627 AD) of the Ming Dynasty (Figure 3b).
The findings of earthenware jars based on their size consist of large and small jars. There are seven
large jars and two small jars. The jars are glazed brown, and three of them have four ears. The jars are
all incomplete (Figure 3c). In the water area of the Soasio Site, there are interesting remains in the
form of rock formations deliberately arranged from ancient times that look like wave breakers or
beach protectors (Figure 3d).
Figure 3: Documentation of UCH in Tidore Islands; shipwreck indication (a); ceramic findings (b); jars and
earthenware findings (c); bird’s eye view of Soasio site (d)
The ecosystem around the Soasio site is covered by coral reefs, of about 60% (good condition) at a
depth of 4-15 m, with the basic contour being a reef slope. The coral reef genera found included:
Acropora sp, Merulina sp, Giniastrea sp, Montipora sp, Porites sp, Pectinia sp, Symphyllia sp, Favia
sp, Astreopora sp, Montastrea sp, and Diploastrea sp (Figure 4a). Meanwhile, the types of fish found
were indicator fish or associated fish and target/economic fish such as grouper, snapper, and pelagic
5
�fish (Figure 4b). The seafloor substrate consists of rubble/dead coral rubble, sand deposits and
sediment resulting from landslides around the coast (Figure 4c). Based on the results of the calculation
of the tourism suitability index, the Soasio site is included in the quite suitable category with a value
of 73.02%. The suitability index value is based on the water brightness parameter, coral community
cover, life forms, types of reef fish, archaeological site depth, current velocity, and reef depth.
Figure 4: Biodiversity in the surrounding Soasio site; coral covers (a); fish ecosystem (b), sediment substrate (c).
UCH in Tongowai Site
The Tongowai site at a depth of 37-42 m is where the cannon was discovered. The artefacts found at
the Soasio site are more scattered than at the Tongowai site. According to locals documented in
Rahmawan et al. (2021, 175), the observed cannon was an artefact left over from salvage conducted in
1998 (Figure 5a). Another cannon, earthenware, and ceramics were removed in 1998 by a Japanese
company and are in the government house of Halmahera Tengah Regency (Figure 5b). The condition
of the pottery was not conserved, so a white surface was observed due to salting (Figure 5c).
The brightness or visibility on the seabed of the Tongowai Site reaches 25 m. The bottom contour of
the Tongowai waters is made up of reef flat and reef slope, with the bottom substrate consisting of
dead coral fractures and sand deposits. Coral reefs are found at depths from 1 - 25 m with
concentrations of dense coral cover at depths of 2 - 10 m. Percentage Cover (PC) of live coral reaches
6
�50 % (Good Condition…Figure 5d). The coral genera that can be found include: Acropora.sp,
Montipora sp., Seriatopora sp., Oxipora sp., Porites sp., Stylopora sp., Pectinia sp., Psammocora sp.,
Galaxea sp., Fungia sp., Pocillopora sp., Favia sp. and Hidnopora sp., Goniastrea sp., and there are
sponges, soft corals, and sea fans/Gorgonians. Based on the results of the tourism suitability index
calculation, the Tongowai site's location is categorized into entirely appropriate for tourism with a
value of 77.8%.
Figure 5: Documentation of UCH in Tidore Islands; underwater cannon finding (a); excavated cannon from
Tongowai site (b); A pile of earthenware (c); coral covers and ecosystem in Tongowai site (d).
Maritime and Underwater Heritage Trail Developments
The places where the shipwreck and the underwater remains do exist in the Tidore Islands have
potential for marine tourism, especially for underwater diving objects. Based on the process of
identification and analysis of the data, a strategy for further protection and development of sustainable
UCH in the Tidore Islands can be initiated. The formulation of the management strategy for
developing underwater archaeology potential in the Tidore Islands is shown in Table 1.
7
�Table 1: The formulation of the underwater heritage trail development strategy.
No
Identified Criteria
Strategic Plan
Aligning the vision and mission makes the Soasio and Tongowai
1
Mutual commitment
sites sustainable tourist destinations
Involve community members in decision making.
2
People empowerment
Ensure that local communities receive benefits.
Ensure environmental sustainability.
Develop a tourist image (brand image) Gurabunga in line with the
existing tourism image in the area.
Raising the history of various old buildings in the Tidore Island area,
especially Tongowai and Soasio site
Environmental conservation.
3
Village attractiveness
Preservation of traditional customs and culture
Development of tourism product packaging in the form of
enrichment of tourist attractions, development of tourism packages,
and integrated tourism promotion.
Provision of supporting facilities for local product development.
Develop tour packages in Soasio and Tongowai village.
Education and training on village tourism and tourism awareness.
Tourism-based entrepreneurship courses/training for residents of
productive age and school dropouts in order to develop local crafts,
4
Human resource development
souvenirs, etc.
Intensive guidance to local guides on tourist assistance (especially
climbing guides).
Provide knowledge to the public about UCH.
Formation of tourism awareness group.
Increase the creativity of the existing community.
Provide capital strengthening for the provision of support for tourism
development, both for business capital for souvenirs and capital for
5
Villagers’ motivation
supporting equipment for artistic attractions.
Equipping tourist companions, especially diving companions, and
providing adequate diving support equipment.
Encouraging local regulations that facilitate licensing of business
operations in the tourism sector in Soasio and Tongowai villages.
Planning and development of facilities & infrastructure adapted to
the concepts and strategic plans of tourist destinations (coordination
with Indigenous elders and the Tidore city government).
Building support facilities for unique traditional tourism activities.
Prioritizing the development of road infrastructure to facilitate access
for tourists to Tongowai and Soasio Sites and adjacent villages.
Re-enable the security post along with the security forces or officers,
6
Facility and infrastructure
to avoid criminal acts while in the tourist area.
The addition of a homestay in an adequate resident's house.
Public toilet construction.
Make a spatial/land use plan in the context of developing an
environmentally friendly tourist village.
Install mooring/marking buoys on the two sites (Figure 8a).
Promoting Soasio and Tongowai to various mass media, namely print
media, electronic media and also online media.
Make booklets and leaflets containing information on Soasio and
Tongowai Village and guidebooks about UCH tourism.
Conduct counselling and socialization for tourism actors.
7
Promotion
Holding various events related to Tidore UCH.
Participate in national tourism festival events or exhibitions.
Installation of information boards (heritage trail) that tell the history
of the sinking of the Trinidad ships and the history of the presence of
the Spanish and Portuguese in Ternate-Tidore (Figure 8b).
8
�The right strategy for developing tourist destinations in Tidore UCH is through Community-Based
Tourism, which reflects the diversity of culture, traditions, natural beauty, crafts and cuisine. Aim to
become the local identity with a concentration of tourist destinations that does not compete for
tourists.
ACKNOWLEDGEMENTS
We would like to thank Research Institute of Coastal Resources and Vulnerability (RICRV), Ministry of Marine Affairs and
Fisheries, Indonesia for research funding in 2019 and 2021 in Ternate-Tidore. Gratitude is also given to the local
communities of Tidore who have assisted during the field surveys.
BIBLIOGRAPHY
Fahri, J., Abubakar, R. and Alhadar, F.M. “Strategy for developing excellent tourist destination (A case study of Gurabunga
Village, Tidore Island Municipality, North Maluku).” Journal of International Conference Proceedings 5, no.1
(2022): 1-12.
Irani, H.R., Golverdi, M., Rastegar, R. and Rezaei, S. “Rapid ecotourism development and challenges: the case of ecolodge
in Iran.” Tourism Recreation Research (2022):1-6.
Kader, Abdurrahman. "Development planning of tourism destination as local superior economy sector: study at Tidore city
islands." International Journal of Management and Administrative Sciences 5, no. 3 (2017): 19-25.
Masberg, B.A. and Morales, N. “A case analysis of strategies in ecotourism development.” Aquatic Ecosystem Health &
Management 2, no.3 (1999): 289-300.
Rahmawan, G.A., Ridwan, N.N.H., Wisha, U.J., Ilham, I., Gemilang, W.A., Andriani, F.W., Sudaryadi, A. and Irwansyah, I.
“Ekowisata Terintegrasi Situs Kapal Tenggelam di Tidore Kepulauan, Maluku Utara.” Jurnal Kelautan Nasional 16,
no. 3 (2021): 169-184.
Runtunuwu, P.C.H. “Tourism sector development strategy in North Maluku: A case study of Tidore Islands.” International
Journal of Tourism and Hospitality in Asia Pasific 3, no. 3 (2020): 1-8.
Sosmiarti, S. and Fahlefi, U.A. “Pengembangan Potensi Wisata Sejarah Dan Kearifan Lokal Masyarakat Soasio Melalui
Program Paket Wisata Dan Rumah Budaya Sebagai Pusat Kesultanan Tidore.” Buletin Ilmiah Nagari Membangun 2,
no. 2 (2019): 94-108.
Wijayanti, H., Marfai, M.A., Mutaqin, B.W., Hadmoko, D.S., Lavigne, F., Faral, A. and Riasasi, W. “Ecotourism in a
Hazardous Small-Volcanic Island: Tidore Island, Indonesia.” IOP Conference Series: Earth and Environmental
Science 1039, no.1 (2022): 12021.
9
�
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2023 Session 21: New Technologies and Interdisciplinary Strategies for the Promotion and Protection of Maritime Cultural Heritage
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Session 21 papers
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Papers presented at Session 21 of the 2023 Asia Pacific Regional Conference on Underwater Cultural Heritage
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Asia Pacific Regional Conference on Underwater Cultural Heritage
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The Museum of Underwater Archaeology
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November 2023
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Asia Pacific Regional Conference on Underwater Cultural Heritage
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English
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Asia Pacific Regional Conference on Underwater Cultural Heritage
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The Potential of Maritime Archaeology (Shipwreck Sites) for Sustainable Marine Tourism Management and Strengthening Historical Narrations in Tidore, North Moluccas, Indonesia
Description
An account of the resource
The potential of shipwreck site resources in “Spice Routes,” Ternate-Tidore, reflects several historical pieces of
evidence relating to archaeological remains from the Portuguese and Spanish eras in the surrounding sea and
coastal areas. In the 1990s, a plethora of archaeological remains were salvaged. An integrated archaeological
study is an initial step to optimize the use of underwater archaeological resources in the area of interest. The
survey consisted of local coordination, expert consultation, literature study, field surveys and underwater
observations, mini excavations using water dredging, artefact samplings site measuring and documentation,
artefact desalination, and C14 carbon dating analysis for wooden materials found within the site. Moreover, the
water quality survey for marine tourism interests and Trinidad ship reconstruction is significant in supporting
500 years of circumnavigation of the earth by Ferdinand Magellan and Juan Sebastian Elcano and supporting
publication and dissemination. Based on the present study, it is observed that Soasio and Tongowai sites have
the potential to be developed as the centre of integrated marine ecotourism with maritime archaeology-based
sites. This consideration is due to plenty of historical artefacts and tourism feasibility assessments. Therefore,
local and regional regulations relating to regional spatial planning are crucial before implementing the
ecotourism project in this area.
Creator
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Wisnu A. Gemilang
Nia N. H. Ridwan
Guntur A. Rahmawan
Ulung J. Wisha
Publisher
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The Museum of Underwater Archaeology
Date
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2023
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English
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Gemilang, Wisnu A., Nia N. H. Ridwan, Guntur A. Rahmawan and Ulung J. Wisha. 2023. “The Potential of Maritime Archaeology (Shipwreck Sites) for Sustainable Marine Tourism Management and Strengthening Historical Narrations in Tidore, North Moluccas, Indonesia.” Edited by Jennifer Craig, Jay Mok, T. Kurt Knoerl, and Hans van Tilburg. In Proceedings of Fifth Asia Pacific Regional Conference on Underwater Cultural Heritage: Gwangju, The Republic of Korea, November 13-18 2023. The Museum of Underwater Archaeology. URL: https://apconf.omeka.net/exhibits/show/apconfproceedings/item/1916
Asia-Pac Session 21 2023