PCI Geomatics is supporting the geodata efforts of the United Nations by providing technology and supporting training to help produce accurate and up-to-date digital elevation models (DEMs) using affordable ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer) data. The United Nations will be producing DEMs in order to support the growing data demand by humanitarian efforts in third world nations where accurate DEMs are vital but largely unavailable or simply do not exist.
Extracting a DEM automatically from ASTER data is a straightforward procedure using PCI Geomatics software. DEMs created from ASTER imagery can be expected to have a vertical accuracy as high as 11 meters in areas that are clear of vegetation or man made features. Elevation models of this accuracy can be used in areas where DEMs are currently not available, or as an alternative to commercial DEM data products.
In addition to creating the new DEM, ASTER (or other imagery) can be orthorectified using either the DEM generated with PCI Geomatics software or by using any other DEM available for the area. Orthorectification is the geometric correction process by which distortions in the imagery caused by the sensor and the terrain are removed. The output orthoimage can then be used for meaningful ground measurements and can fit with existing map data. Technical papers and discussion of the subject of creating DEMs and digital orthoimages from ASTER imagery can be found on the PCI Geomatics company web site (www.pcigeomatics.com).
The ASTER system, flying on the Terra satellite platform, is a cooperative effort between NASA and Japan’s Ministry of Economy, Trade and Industry (METI) and the Earth Remote Sensing Data Analysis Center (ERSDAC). Extremely affordable and accurate, ASTER is used to obtain detailed maps of land surface temperature, emissivity, reflectance and elevation. The resulting DEM and orthoimagery created from ASTER imagery using PCI Geomatics software can be used in support of an impressive range of geomatics applications.