This map illustrates satellite-detected areas of landslide damage in the village of Ab Barek, Badakshan, Afghanistan. Following heavy rains in the region, a landslide partially buried Ab Barek on 2 May 2014. Using a satellite image acquired 5 May 2014 by the WorldView-2 satellite, UNOSAT delineated the landslide area. In addition, areas of IDPs, relief operations, and water pooling due to the landslide are indicated as of 5 May. The 5 May 2014 image was compared to an image from 7 June 2013 in an attempt to determine how many structures were buried, and a total of 87 such structures were located. However, between 7 June 2013 and the occurrence of the landslide Ab Barek had changed and grown considerably, and thus its possible additional buried structures exist which are not identified in this analysis. This is a preliminary analysis and has not yet been validated in the field. Please send ground feedback to UNITAR / UNOSAT.
UNOSAT datasets and maps are produced using a variety of methods. In general, analysts closely review satellite imagery, often comparing two or more images together, and determine notable changes between the images. For damage assessments, refugee or IDP assessments, and similar analyses, these changes are then manually documented in the vector data by the analyst. For flood extractions, landcover mapping and similar analyses, a variety of automated remote sensing techniques are used to extract the relevant information which is then reviewed and revised as necessary by the analyst. In all cases, resulting data is then loaded into a standardized UNOSAT geodatabase and exported asshapefiles for dissemination.
Caveats / Comments
This is a preliminary assessment and has not yet been validated in the field. It is important to consider the characteristics of the source imagery used in the analyses when interpreting results. For damage assessments it should be noted that only significant damage to the structural integrity of the buildings analyzed can be seen in imagery, while minor damage such as cracks or holes may not be visible at all. For flood extractions using radar data it is important to note that urban areas and highly vegetated areas may mask the flood signature and result in underestimation of flood waters. Users with specific questions or concerns should contact email@example.com to seek clarification.