Figure 1. Orientation of The Seven Countries in The Horn of Africa
Several organizations have created web-based and freestanding GIS to support humanitarian relief projects for the Horn of Africa. The United Nations, Humanitarian Assistance Information Center, and the US Department of State are working in concert to produce a geospatial data system that will support humanitarian relief efforts for natural disasters and political upheaval. Various data sources have been searched and pertinent information retrieved. What is lacking are landuse maps and some form of physical imagery to see what is happening on the ground. A global mapping project sponsored by NASA and NIMA, has provided Landsat imagery and landuse maps from that imagery for the continent of Africa. Landsat imagery and a 13-class landuse map created from that imagery are delivered through an Esri ArcIMS™ site for the Horn of Africa. This presentation outlines the development and implementation of the remote sensing in support of humanitarian relief in eastern Africa.
In January 2001, the US Department of State (DOS) made a request of NIMA for aid in generating humanitarian planning maps for countries in the Horn of Africa: Djibouti, Eritrea, Ethiopia, Kenya, Somalia, Sudan, and Uganda (Figure 1). The maps were to assist relief workers in the planning of humanitarian efforts to relieve suffering associated with natural and man-made disasters. The data were to be accessible through an on-line mapping system utilizing Esri's ArcIMS™ software (Figure 2). Earth Satellite Corporation of Rockville, Maryland was retained to create the web site and populate the mapping system with raster and vector data sets.
Data layers--population, topography, hydrology, land cover, refugee camps, airfields, transportation, and natural hazards--were to be compiled in a common reference system (geographic) allowing for direct overlay of disparate data. Orthorectified Landsat imagery, produced by EarthSat's GeoCover Ortho program were included, as well as land cover data from EarthSat's GeoCover LC program.
Earth Satellite Corporation was chosen to develop the Horn of Africa mapping system based on existing capability and expertise; EarthSat has been a provider of remote sensing and GIS data and analyses for over 30 years, and has been delivering data over the Internet since ArcIMS was released in June of 2000.
Humanitarian organizations working in the Horn of Africa use data to support aid for a wide range of needs: famine, war, refugee displacement, and natural disasters. Having data prepared in advance of a crisis allows for a more rapid response. The United Nations Office for the Coordination of Humanitarian Affairs (OCHA) has initiated field-based information management activities through its Field Information Support Project. ReliefWeb's Map Centre provides easy access to humanitarian maps from a wide variety of sources. The Horn of Africa ArcIMS Site was designed to provide a dynamic mapping capability and to support field operations through access to base geographic data.
Although all data was public, sometimes it was necessary to consider the implications of publicizing a data set, e.g locations of refugee camps. How to display disputed boundaries was another issue. EarthSat modified a version of the DCW political boundaries that indicated unresolved boundaries, posted on the web site with a disclaimer.
The Department of State had several criteria for the dynamic mapping system. Data included must be open to public access and the system should be somewhat intuitive and easy to use once familiarity with the tools is accomplished. A set of on-line help tools and metadata for each layer should be available, and paper maps should be printable from the system. Once developed, the ArcIMS site would be turned over to OCHA and made available through ReliefWeb. The archive of supporting data (over 100 GB) would be housed in Nairobi, Kenya at a Horn of Africa regional center. Concurrent with the development of the ArcIMS site, the plan for the regional center was developed, now called the Data Exchange Platform for the Horn of Africa (DEPHA).
To meet the requirements EarthSat created a set of ArcIMS map services linked through contextual menu picks and predetermined views for each of the seven countries. Although each map service has predetermined view parameters for which data layers are loaded and viewed, the user can easily, in real- time, alter the map layers to meet specific goals.
Relief planners often need data that is specific and current, and this is often difficult to find in a format that can be immediately incorporated into a mapping system. Most of the data on this ArcIMS site is from national and global data sets which are, on average, 5-10 years old. Rather than trying to support the complete data needs for humanitarian planning, the goal of the ArcIMS site was to provide base layers that help set the larger context when specific issues are to be examined. In the future, as more data becomes available in digital form, the more powerful ArcIMS will be as a query and analysis tool.
Landsat TM (c.1984-1990), 28.5 m resolution, imagery displayed in a false color band combination (RGB=742) to bring out contrast in non-vegetated areas. Earth Satellite Corporation
LandScan 2000 Population Estimate Population per square km. Modeled population, worldwide, 30" x 30" resolution. Weighted factors used as model input include census counts, roads, land cover, and slope. Oak Ridge National Laboratory
GeoCover Land Cover 13-class land use/land cover classification derived from Landsat TM (c. 1984-1990), 1.4 ha MMU Earth Satellite Corporation
IGBP Land Cover (International Geosphere Biosphere Programme) 17-class land use/land cover derived from AVHRR data (April 1992-March 1993), 1 km resolution. USGS EROS Data Center
GTOPO 30 Elevation Elevation in meters above sea level, completed in 1996 , approximately 900 m resolution. USGS EROS Data Center
Refugee Camps Locations as of April 1, 1999. United Nations High Commissioner for Refugees
Volcanoes Magnitude and year of explosion. National Geophysical Data Center Natural Hazards Data World Wide Volcano Database
Earthquake Intensity Zones Estimate of earthquake effects on the surface of the earth, derived from historical reports and multiple parameters, which include ground acceleration, duration, and subsoil effects. Zones show probable maximum intensity once in 50 years. UNEP/GRID-Geneva
Digital Chart of the World (DCW) Derived from DMA (NIMA) ONC Series maps (1:1,000,000); completed in 1993. Includes roads, railroads, transportation, airfields, utility lines, rivers, and political boundaries.
Populated Places Geographic Names Data Base U.S. Board of Geographic Names, NIMA
The largest investment of time for the ArcIMS site was the initial setup of the web pages and preparation of the data. Preparation of data was mainly to reduce file sizes for faster Internet browser display. This was most important for the Landsat tiles, which were reduced using MrSID compression, and for some of the detailed vector coverages. Large data files are a difficulty for both ArcIMS and Internet and they can immobilize a website with slow downloading/drawing time. Generally raster files are slower to draw than vector files but file size is the main factor: a low-resolution raster image will draw more quickly than a detailed vector file.
The goal of the Horn of Africa ArcIMS site was to provide a data platform, available to many, to be used as a planning tool from which basic queries could be performed and maps could be printed. ArcIMS is strong as a data display tool and a quick map maker, and offers basic GIS tools such as queries, measurement and buffering, with only Internet browsing software. Since not everyone has an Internet connection, and access will vary depending on the user's hardware and the Internet infrastructure in a particular region., alternative data delivery formats can be developed along with an ArcIMS site, such as bundling data with ArcExplorer and distributing it on CDs.
1 The United Nations Office for the Coordination of Humanitarian Affairs (OCHA) is responsible for supporting coordination among the UN response agencies as well as the humanitarian community during natural disasters and complex emergencies.
Stacy Hoppen
Senior Application Scientist - Earth Satellite Corporation - 6011 Executive Blvd., Suite 400 Rockville,
MD 20852 301-231-0660-voice Shoppen@earthsat.com
Robert T. Paulsen
Senior Scientist - Earth Satellite Corporation - 6011 Executive Blvd., Suite 400 Rockville, MD 20852
301-231-0660-voice rpaulsen@earthsat.com