Volume 1, Issue 1

Towards a New Humanitarian Technology: The ENVIREF Project

Environmental Monitoring of Refugee Camps using High-Resolution Satellite Images
Objective: The overall objective of ENVIREF is to develop and evaluate new and improved products and methods from high-resolution earth observation (EO) satellite images for application and exploitation in humanitarian relief operations.

The ENVIREF partners work on defining user-needs, developing new and improved products and methods, and demonstrating satellite EO products for the relief community in order to make relief operations more efficient. To ensure input from end-users, several international relief agencies are involved in ENVIREF, such as United Nations High Commissioner for Refugees (UNHCR), International Federation of Red Cross and Red Crescent Societies (IFRC), Medecins Sans Frontieres (MSF) and Oxfam UK.

Satellite imagery of various types were acquired and analyzed for three different study areas, including several refugee camp settlements in the Kosovo-Albania-Macedonia border region in Europe, the southeastern part of Nepal in Asia, and the eastern part of Kenya in Africa. Each area represents different climatic, environmental and refugee-related conditions.

Medium-resolution satellite sensors (spatial resolution from 6 to 30m) including LANDSAT TM/ETM+, SPOT, and IRS-1D were used to produce maps of infrastructure, water resources and vegetation cover at an overview level ranging from scale 1:15.000 to 1:250.000. Images from all these sensors can be used to accurately measure the location and extent of a refugee camp, although the spatial resolution is not good enough to reveal any details within a camp area, e.g. to identify independent residences, roads, and so forth.

Water bodies derived from the satellite imagery were combined with digital elevation data in order to determine river flow direction. Vegetation cover mapping was performed both with and without additional information, e.g. from field observations or available vegetation maps. Without any supporting information about the vegetation in an area, only very general assumptions can be made, such as the location and distribution of forest. These maps can, on the other hand, be prepared very quickly, and also be used to plan where in situ measurements should be performed. With additional information about the vegetation, more detailed maps can be prepared, showing, for example, the distribution of various vegetation types.

Satellite images with only 1m spatial resolution from the IKONOS satellite were used to perform mapping of details such as roads, footpaths, separate buildings, tents, and water sites inside the refugee camp area. This is the first satellite to deliver very high-resolution satellite imagery on the commercial market. An especially important result of the IKONOS-data analysis is the potential for identifying single tents and buildings inside a camp area. For the investigated camp settlement in Nepal, close to 100% of all present tents and buildings were identified and could be counted in the image. This information can be used to make better estimates of the number of people living in a camp, which is important for determining the amount of food and medicine needed. IKONOS images also have the potential to be used for detailed planning of refugee camps, including expansions, and assessments of environmental changes in the immediate surroundings.

We find that by providing fast access to general thematic information over a larger region the LANDSAT-7 ETM+ sensor could be a valuable data source for the relief community. The sensor could be especially helpful due to both the global data archive and the low price of only US$600 per image. For performing more detailed analysis, which is especially needed in the later stages of a crisis situation, images at a resolution available from the IKONOS sensor are needed.

The data set for the Nepal study includes one IKONOS scene (pan+ms), one LANDSAT-7 ETM+ scene, two SPOT XS scenes, two ERS SAR scenes, as well as several topographic maps at scale 1:25,000, including a DTM for the area surrounding the Beldangi camp area. Some aerial photographs over the Beldangi camp area could also be obtained.

In addition to the above mentioned, the analysis of the IKONOS image from the Nepal case study includes land use classification, automatic detection of buildings and shelters within the camp, as well as determination of best-camp-location using GIS.

  Detailed subset from refugee hosting area in Chiapas, Mexico. This image illustrates the details possible to distinguish using 2 m panchromatic (black and white) very high-resolution satellite images. Individual tents and houses can be identified, and narrow paths can be detected.
Example of images and maps from the project can be found on http://www.enviref.org. ENVIREF is a shared cost project supported by the European Commission’s 4th framework programme through DGXII. Project partners are the Nansen Environmental and Remote Sensing Center, Norway; the Swedish Space Corporation, Sweden; Infocarto, Spain; United Nations High Commissioner for Refugees, Switzerland. The Project coordinator is Ola M. Johannessen of the Nansen Environmental and Remote Sensing Center. She can be reached at Ola.Johannessen@nrsc.no.

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