MapReady: An Open Source Tool for the Utilization of SAR in Geospatial Applications

Users of remote sensing data can now benefit from the wide availability of Synthetic Aperture Radar (SAR) satellites, including ERS-2, RADARSAT-2, ALOS PALSAR, Envisat, and TerraSAR-X. As an active sensor, SAR can acquire data independently of weather and at any time of day or night. Unfortunately, SAR data has not seen wide-spread usage by those engaged in mapping or Earth studies. The reason for this is two-fold: 1) the data comes in a format that most geospatial tools cannot ingest, and 2) SAR imagery is subject to geometric distortions that keep it from being co-registered with more conventional imagery. The Alaska Satellite Facility (ASF) has developed the free, open source MapReady Remote Sensing Tool Kit to facilitate the use of SAR data for even novice users of geospatial data. Through MapReady's intuitive GUI interface, the user is able to ingest a SAR image in its native format and process it to an orthorectified image in GeoTIFF format; ready to be used as a layer in a geographic information system (GIS). This presentation will outline the challenges facing the user of SAR and show how they are overcome through the use of MapReady. The principal innovation in the newest generation of SAR satellites is the implementation of polarimetric SAR, for which data exists in two or more polarizations. Like the bands in optical data, polarimetric bands reveal a great deal about targets in the imagery. In its most recent version, MapReady includes the ability to perform polarimetric decompositions and classifications. Specific examples will be shown using polarimetric data from the ALOS PALSAR sensor. Derived products will be analyzed and interpreted to show how SAR polarimetry can be used to perform land classification and identify land change.