Programs: Science and Policy
AAAS Scientific Responsibility, Human Rights and Law Program
High-Resolution Satellite Imagery and the Destruction of Housing Structures in Negeha, South Darfur
The Darfur region is an area that continues to experience conflict, and remains an area of interest for the American Association for the Advancement of Science (AAAS) and Amnesty International, as evidenced by the Eyes on Darfur project. Part of Eyes on Darfur focuses on a series of "Villages at Risk." These are villages that were deemed in danger of being attacked. AAAS periodically acquires imagery of these 13 locations to determine if they have experienced attacks. Four of these locations were documented to have sustained attacks in 2008-2009, which is documented on the project web site. In December 2010, reports were published by ReliefWeb regarding new attacks in the Negeha area of South Darfur, which is within the "Villages at Risk" study area. The AAAS Science and Human Rights Program undertook a survey of the area. The survey, looking for evidence of violence, covered approximately 96 square kilometers in the Negeha area. The fighting is said to have resulted in burned homes and newly displaced persons in Negeha and surrounding areas (Figure One). To determine the extent of the destruction, AAAS initially examined satellite imagery of the area taken on December 31, 2005 and December 24, 2010. AAAS documented several hundred damaged or destroyed structures.
Following this initial effort, an image from January 13, 2010 was acquired to narrow the time frame of the analysis. After reviewing this image, two phases of destruction in the Negeha area were identified. AAAS ultimately found 265 structures damaged or destroyed between December 2005 and January 2010, and an additional 554 damaged or destroyed between January 2010 and December 2010. Figure Two shows these structure counts for seven village areas covered by the imagery.
II. Methods and Technologies
According to a report by ReliefWeb, the villages of Negeha and Jaghara were burned in December 2010, resulting in more than 7,000 internally displaced persons. AAAS examined Negeha and its surroundings for signs of violence by analyzing high-resolution satellite images taken before and after the reported events.
The earliest image used in the study was captured by DigitalGlobe's QuickBird satellite on December 31, 2005. This image was available on the Google Earth platform. The next image, from January 13, 2010, was acquired by GeoEye's GeoEye-1 satellite. The final image, taken after the reported violence, was acquired by DigitalGlobe's WorldView-2 satellite on December 24, 2010. These three images were visually compared using the ERDAS Imagine and ESRI ArcMap software packages.
AAAS identified housing and other structures that were visibly intact in 2005, but which appeared to have been destroyed shortly prior to January 2010. Other structures were found to have been damaged between January 2010 and December 2010. While many of the changes to structures appear to be a result of attacks on the community, other changes may be attributed to rebuilding, families relocating, and other non-conflict related factors.
Destroyed structures were identified by their fuzzy, undefined outlines, their dark appearance due to charring from fire, and their lack of shadows. An intact house tends to cast a darkened shadow along the wall opposite the sun. A burned structure will often have had its roof collapse and its walls crumble, meaning it will no longer cast a significant shadow. Fires may also leave the ground appearing blackened and charred from the scattering of ash. Similar evidence of violence was found throughout the Eyes on Darfur project, which analyzed imagery of several communities close to Negeha.
In total, 819 individual structures were identified as damaged or destroyed. Of these, 265 suffered damage between December 2005 and January 2010, while 554 did so between January and December 2010. Figure Two shows the extent of damage in the area of interest and the time periods during which it occurred. Figure Three depicts an overview of damage in the Negeha region as detailed in Figures Four through Eight.
The image on the left, from December 31, 2005, shows a community of intact structures. By the January 13, 2010 image on the right, 206 structures in the settlement (whitish-gray color) have been completely destroyed. Additionally, seven structures were found damaged between January and December 2010. (12.898 N, 25.408 E) Left image courtesy of Google Earth. © 2011 DigitalGlobe, Inc. Right image © 2011 DigitalGlobe, Inc.
The Negeha analysis conducted by AAAS involved a review of satellite imagery from December 2005, January 2010, and December 2010.
The analysis revealed charred earth and hollowed structures affecting 554 structures in total, largely corroborating
reports of an attack on the area in December 2010. Given the findings in this report, AAAS will continue to monitor
the region as reports of attacks are reported by ReliefWeb and other humanitarian organizations. V. Further Resources
V. Further Resources
- A PDF of this report can be found here.
The satellite imagery and analysis are available through this Google Earth layer.