Operational use of RADARSAT-1 fine stereoscopy integrated with Landsat-5 thematic mapper data for cartographic application in the Brazilian Amazon

Abstract

The feasibility of topographic mapping through orbital remote sensing was investigated for the Brazilian Amazon. The study area is in a region of low topographic terrain within the Tapajós National Forest. Two kinds of radargrammetric digital elevation models (DEMs), one based solely on satellite ancillary data and one calibrated with ground control points (GCPs), were produced based on a fine RADARSAT-1 stereopair (F2/F5) and evaluated regarding accurate field planialtimetric measurements. The geometric modeling for the DEM extractions was based on the RADARSAT-1 specific model from OESE software (PCI Geomatics Inc.). The planimetric features were extracted from integrated fine and Landsat thematic mapper (TM) products. Precise topographic field information from a differential global positioning system (DGPS) was used as GCPs for the modeling of the DEMs and for the orthorectification of the synthetic aperture radar (SAR) and optical data and as independent check points (ICPs) for the calculation of planialtimetric accuracies of the products. The investigation has shown that the accuracy of the topographic map met the requirements for a 1 : 100 000 scale map (class A) as requested by the Brazilian Standard for Cartographic Accuracy. The approach is a realistic alternative for topographic mapping at a semi-detailed scale in similar environments of the Amazon, where terrain information is seldom available or is of low quality.