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Seychelles Research Expedition Surveys Remote Islands
The Implementation of GIS Technology Aids Marine Habitat Interpretation

By Amanda Williams
Marine Science Geographic
Information System Analyst
Khaled bin Sultan
Living Oceans Foundation
Landover, Maryland

and
Nancy Sappington
Writer
ESRI
Redlands, California



Web-based, interactive geographic information system (GIS) data viewers provide a multitude of benefits to users who have Internet access but may lack formal GIS training. In addition to reaching out to a broader community than just trained GIS specialists, viewer users (e.g., natural resource managers, scientists and students) do not need to store data in-house, but still have easy access to query tools and the ability to generate detailed documents on an area of interest. Thus, greater ease of access and use of geospatial data is achieved, eliminating the costly barriers to obtaining GIS software and training.

Greater access to information to improve the publicís understanding of oceans and promote ocean conservation and restoration was one of Saudi Arabian prince Khaled bin Sultanís goals when he established the Living Oceans Foundation in 2000.

In 2009, the foundation, in collaboration with the Center for GIS at Towson University (CGIS), launched a progressive online ArcGIS server viewer, displaying sophisticated compact airborne spectrographic imager (CASI) data from an expedition to the Seychelles in 2005.

The Seychelles GIS viewer allows users to manipulate data according to their research needs, at no cost, as long they have access to the Internet. It is one of the first viewers of its kind in mapping benthic habitats and features a unique habitat-reporting tool designed specially for this application by Towson University, setting the precedent in online benthic habitat querying capabilities.

The Seychelles viewer utilizes the ArcGIS server for a fast, high-resolution GIS product. (Image courtesy of Khaled bin Sultan Living Oceans Foundation)
The Expedition
The data used for the Seychelles GIS viewer were gathered during a two-week period in January 2005, when the foundation participated in a collaborative research expedition in the Republic of Seychelles in the western Indian Ocean with the Cambridge Coastal Research Unit of the University of Cambridge and the Seychelles Centre for Marine Research and Technology-Marine Parks Authority.

The project focused on the Amirantes Archipelago, a group of coral islands, reefs and shoals located in the Seychelles Outer Islands. Historically isolated and remote, the islands are rich in rare flora and fauna, and the marine life around the islands is spectacular, with more than 1,000 species of fish having been recorded. The reefs and islands of the southern Seychelles are poorly documented, and this scientific survey was the first for some of the islands.

The expedition had two main goals: to conduct aerial mapping of numerous islands and their surrounding reefs in the southern Seychelles and to conduct surveys of the benthic and fish communities of these reefs and describe them.

The researchers implemented GIS technology to communicate the results of their studies, and through a collaboration with CGIS, natural resource managers engaged in marine planning can now easily view the habitat maps developed from the Seychelles project online via the ArcGIS server application.

Alphonse Island is an atoll, as shown here by a benthic habitat map.
Creating Benthic Habitat Maps
Given the large area that needed to be surveyed in a relatively short period of time, a combination of remote sensing and in-situ scuba surveys was used to map and classify the terrestrial and benthic habitats.

Remote sensing allows for greater area to be covered, in addition to completing habitat profiles for each island. Scuba surveys provide greater detail on the benthic cover and are used to validate remotely sensed data, known as ground truthing.

While the Living Oceans Foundationís Golden Eye seaplane collected aerial imagery, scientific personnel onboard the research vessel MY Golden Shadow were involved in extensive ground truthing data collection.

The CASI sensor was mounted on the seaplane and configured to record electromagnetic data in 17 bands. Flying in parallel lines over the areas of interest, the team identified 25 habitat classes, such as coral, sea grass, bare coral rock, macroalgae or sand. The exact position and the habitat observed at that exact position was recorded using a global positioning system. By knowing which category was represented by the colors on the CASI image, each pixel within the CASI image could be assigned a relevant category. This method helped the team assemble the maps of the larger areas in a relatively short time.

The CASI mapping was supported by shallow marine surveys for both benthic cover characteristics and biomass. Scuba diving gave the researchers the opportunity to assess coral condition, including assessing recovery from the coral mortality associated with a 1998 seawater warming event. The divers used underwater videography along 20-meter transects at a range of water depths. The technique provided the researchers with rapid collection of objective and comparative reef health data.

When the fieldwork was completed, the team processed the raw data into classified habitat maps for each geographic site, comparing computer-generated habitat classes with aerial photographs, ground truth data and existing maps and publications for accuracy. Twelve habitat maps were generated—10 from the Amirantes Islands and two from the Alphonse Group—which are now available in the Atlas of the Amirantes.


Interactive Data Viewer
Four years after the expedition, the Living Oceans Foundation partnered with CGIS to develop custom tools for exploring the benthic and terrestrial habitat maps using the ArcGIS server from ESRI, making the information much more easily accessible.

The new viewer provides features such as zoom levels cached at specific intervals for fast refresh rates or quick zooming. There are detailed instructions about each tool, a help menu and a detailed project description.

The viewer integrates basic tools and functions with specialized querying tools, such as a unique habitat reporting tool and a tool that can measure both lines and polygons in various units of length. In addition to the name and color coding of the legend, CGIS hyperlinked representative photographs of each habitat type into the map legend.

The most innovative feature of this viewer is the habitat reporting tool. Users can draw or define a circle or multisided polygon in various area units (square kilometers, square meters, hectares, square feet, square yards, square miles or acres) or enter a center latitude-longitude. A generated report includes a pie chart depicting the percentage of the query region that each habitat type covers, a color-coded table listing of each legend area in units and percentage of each habitat type, and a table listing of each latitude-longitude corner of the polygon (or circle midpoint). Users can save the report as a PDF document.


Conclusions
ďThe Seychelles expedition was a tremendous success,Ē said retired U.S. Navy Capt. Philip G. Renaud, executive director of the Living Oceans Foundation. ďThe Amirantes group of islands and shallow marine habitats were mapped at high resolution, published in the comprehensive Atlas of the Amirantes by Cambridge University and implemented in an advanced, Web-based, interactive GIS by CGIS. This was truly a collaborative project, and we are grateful for the expertise and creativity of all our partners.Ē

The expedition and the subsequent development of the viewer technology help provide a means for understanding and interpreting the benthic and terrestrial habitats in the Amirantes Islands and Alphonse Group to aid in resource management. Natural resource managers in the Seychelles can now use this information for marine planning and management purposes.

Additionally, as a result of this successful collaboration, the Living Oceans Foundation and the CGIS are in the process of upgrading the Living Oceans Foundationís existing ArcIMS U.S. Virgin Islands application to match the Seychelles ArcGIS server application. The viewers are located within the Living Ocean Foundationís GIS Data Portal, located on the Living Oceans Foundationís website.



Amanda Williams is a marine science geographic information system (GIS) analyst with a masterís in marine science from the University of North Carolina, Wilmington, and a bachelorís in geographical science from James Madison University. She refines GIS data, conducts coral reef photo-transect analyses and assists in project planning at the Living Oceans Foundation.

Nancy Sappington is a writer and editor for ESRI with 16 years of experience in magazine and book publishing.



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