Wetlands on the Web:

Distributing Ramsar Site Information

Center for International Earth Science Information Network at Columbia University (CIESIN)
Gregory Yetman, Antoinette Wannebo, Maarten Tromp, and Robert Bourdeau.

Abstract

Ramsar sites are nationally designated and internationally recognized wetlands under the Ramsar Convention. In an effort to meet the Ramsar community’s data and information needs, CIESIN, a center of Columbia University, is working to provide access to data and information on these important sites through the Ramsar Data Gateway. Satellite-derived data products, socioeconomic information and site-specific data in an integrated database will be made accessible over the web using ArcIMS and SDE. This paper addresses the conceptual and technical challenges of distributing tabular and spatial data and information to a large community with diverse needs.

Introduction

The Convention on Wetlands, signed in Ramsar, Iran, in 1971, is an intergovernmental treaty that provides the framework for national action and international cooperation for the conservation and wise use of wetlands and their resources. There are presently 124 Contracting Parties to the Convention, with 1072 wetland sites, totaling 81.75 million hectares, designated for inclusion in the Ramsar List of Wetlands of International Importance. (Ramsar Bureau web site: http://www.ramsar.org).

Under a Memorandum of Understanding (MOU), the Center for International Earth Science Information Network at Columbia University (CIESIN); an international nongovernmental organization (NGO), Wetlands International; and the Ramsar Bureau, the Secretariat for the Convention on Wetlands, are working together to create an on-line Ramsar Data Gateway to serve as a clearing house for both official and non-official information on Ramsar sites.

Multidimensional data

Once completed, the Ramsar Data Gateway will enable users to perform spatial and attribute queries of both Ramsar and related datasets, conduct basic analysis, display results as cross tabulations and download results over the web. The Ramsar Data Gateway will present access to multidimensional variables from the perspective of a user interested in wetland issues. The multi-dimensionality of the data sets will allow the integration and linkage of variables, thereby more fully exploiting CIESIN’s data holdings and facilitating interdisciplinary analysis. The interface will hide the complexity of the database structure, allowing the user to view the data holdings as if the collection were centered on their particular question. For example, a user could query the database to return the sites that meet the following criteria:

Sites with Commercial Forestry as their principle land use,
Sites found in countries that are signatory to the International Tropical Timber Agreement (ITTA),
Sites found in countries that have a deforestation rate of over 35% in 1995, and
Sites found in countries with a population increase between 1990 and 1995 over 35%;

This query would normally require that 4 separate datasets be consulted. Using the new data model and associated interfaces, this type of query will be possible with a minimum of user effort.

Data Model Description

The Ramsar database has been modeled in an Oracle database using a data model – the Infusion data model, see figure below – developed at CIESIN. The Ramsar dataset, like all datasets, is a collection of variables. Variables are a set of values all of the same type, such as numeric, temporal, or textual. A value can be an individual number, keyword(s), a geographic location, or a note. Variables of the Wetlands International Ramsar Site Database include area, wetland type, land use in wetland and salinity. The variable values of the Ramsar database are organized into a structure that is referred to as the dimensions of the variable. With a known schema, the variables in the Ramsar database can be linked together though their dimensions. For example, a Ramsar site can be linked to treaty information through the country that a site is contained within. In the earlier sample query, the relationships of both sites and treaties to countries were used to identify sites in countries that have signed the ITTA.

The data model is flexible in the presentation of the information because it allows users to access multiple units of analysis. If the user were interested in data related to Ramsar sites, the user could “pick up” the Ramsar Site box and then the linked variables would be accessible through their dimensionality. The unit of analysis in this case would be the Ramsar site. Based on the unit of analysis, the user would then be presented with a series of tools for selecting objects: manual selection tools and criteria-based selection tools.

The Multipurpose Graphical User Interface (GUI)

The Graphical User Interface will provide users with a convenient tool to extract data and information stored in the data model. Multiple data layers and their related tables/variables can be selected to include in the data visualization and analyses.

Integration of Spatial Database Engine (SDE) and the Oracle Data Model

SDE will be used to store the spatial data (raster and vector) accessed through the multipurpose GUI. In this way, the variables will be stored and managed in Oracle, while only the spatial components will use SDE. This allows each program to work with its strength – Oracle with Relational data and SDE with spatial data. Spatial data layers will be linked to variables as necessary for use in the viewer. For instance, Ramsar site information (variables) will be stored in Oracle and linked to their boundaries in SDE via a common identifier. Similarly, country boundaries will be linked with variables on countries (population data, treaty information, etc.) through a set of identifiers. In this way, users can take advantage of the Infusion data model via the GUI to access data. The presentation will vary depending on the active unit of analysis, allowing the user to use both spatial- and variable-based criteria to select, view and manipulate data.

The multipurpose GUI and SDE components of the Ramsar Data Gateway are still under development. In the interim, we have used ArcIMS and the Ramsar Data Gateway to provide query and visualization tools to the Ramsar community.

ArcIMS Internet Mapping Solution

At present, CIESIN enables the user community to access satellite-derived data products, socioeconomic information and Ramsar site-specific data through a prototype on-line Internet mapping application using ArcIMS. This application puts the Ramsar site information in a global context of socio-economic factors such as surrounding land use and population density, through linking several related datasets. The ArcIMS “HTML Viewer” is used on the client side.

Currently the spatial and tabular data are not integrated in one data model. The tabular data is stored in Oracle, and the queries are performed independently of the spatial representation of the data. The spatial data is visualized and analyzed using ArcIMS. The primary entry point for this ArcIMS application is the results page from a query to the Ramsar Data Gateway via the CIESIN site (http://sedac.ciesin.org/ramsardg). The Gateway can be used to select Ramsar Sites by querying the Oracle database. Using the result page there are two main options for further spatial visualization and analysis. The first is to have global overview of the selected sites; the second is to start a regional application zoomed to the individual site.

ArcIMS Server Configuration

ArcIMS Version 3.0
SUN Solaris (SUN Enterprise Server)
Apache web server with Tomcat Servlet

Datasets Utilized

To reduce geometrical distortion, and processing time, the Ramsar sites are grouped into the 6 Ramsar regions Africa, Asia, Europe, Latin America, North America, and Oceania. The data layers of each of the regions are in a Lambert Projection. Datasets linked through the Internet mapping application include:

Vector data:

The Ramsar site boundaries. The Ramsar site boundary collection, maintained by UNEP-WCMC (United Nations Environment Program – World Conservation Monitoring Center) is a collection of boundaries for most Ramsar sites (http://www.unep-wcmc.org).
United States Geological Survey (USGS) Hydro 1 km layers. The rivers and watershed layers of the USGS's EROS Data Center HYDRO1k dataset were used (http://edcdaac.usgs.gov/gtopo30/hydro).
Digital Chart of the World cities.

Attribute data:

The database of Ramsar sites. The database of Ramsar sites consists of the core dataset of the Ramsar convention secretariat maintained by Wetlands International (http://www.wetlands.agro.nl). The database is composed of coded and keyword attribute thematic information for individual sites.
The Directory of Wetlands of International Importance. The directory, maintained by Wetlands International, is a collection of one page summary sheets describing each Ramsar site in a standard format.
The annotated Ramsar list. The annotated Ramsar list, maintained by the Ramsar Bureau, is a collection of short profiles of each Ramsar site (http://www.ramsar.org).

Raster data:

The Gridded Population of the World (GPW) dataset. GPW is a global demographic dataset providing consistent population estimates referenced to a grid of 2.5 x 2.5 minute latitude-longitude quadrilaterals for 1990 and 1995 (http://sedac.ciesin.org/plue/gpw).
The USGS land cover dataset. The Global Land Cover Characterization dataset from USGS EROS Data Center was used (http://edcdaac.usgs.gov/glcc/globe_int.html).

HTML Viewer changes

The default generated HTML Viewer has been customized to enhance the functionality and “look and feel” of the application. Some of the applied changes to the viewer are described below.

The layout of the viewer was changed. For example, the frames were rearranged and the legend was split from the layer list so that it would always be visible.
Help pages were added to the viewer. Users unfamiliar with GIS and ArcIMS need some guidance in the use of the HTML viewer.
The JavaScript functionality was improved. Some of the JavaScript functions can be optimized, such as the source code used to check browser version, and the function to replace characters in strings.
A page was set up so that query coult start the HTML viewer and automatically zoom to and select sites. This required that the SQL limitation on the number of OR statements in one query be overcome. This was achieved by using “Dynamic layer” and AXL “<EXACT>-tag” to visualize selected sites.
A legend for the raster layers was added to the viewer. ArcIMS cannot create a legend for raster layers, so bitmap was created for each raster layer and added to the legend when a raster layer is visible.
The option to download layers was added. Users can download the specific data layers as shapefiles; this features is not implemented in the default viewer. Unfortunately, it was discovered that the Extract Server “sometimes” does not always create zip-files. Periodic restarts of the ArcIMS services is the only solution discovered to date. Additionally, ArcIMS does not delete the zip files created for download, so a crontab demon process was set up on UNIX to delete the zip files.

Gregory Yetman
Antoinette Wannebo
Maarten Tromp
Robert Bourdeau
Center for International Earth Science Information Network (CIESIN), Columbia University