PLANIALTIMETRIC EVALUATION OF A CARTOSAT-1 STEREO PAIR – CASE STUDY: SÃO SEBASTIÃO, SP, BRAZIL
Keywords: IRS-P5, DEM/DTM, Orthoimage, Accuracy, Cartography
Abstract. It is noticed a significant increase in the development of orbital and airborne sensors that enable the extraction of three-dimensional data. So, it's important the increment of studies about the quality of altimetric values derived from these sensors to verify if the improvements implemented in the acquisition of data may influence the results. In this context, as part of a larger project that aims to evaluate the accuracy of various sensors, this work aims to analysis the planialtimetric accuracy of DEM generated from Cartosat-1 stereo pair. The project was developed for an area near the city of São Sebastião, located in the basin of the North Coast of São Paulo state, in Brasil. The relief in this area is very steep, with a predominance of dense forest vegetation, typical of the Atlantic Forest. All points in this assessment have been established in the field, with the use of single frequency (L1) GNSS receivers, through static relative positioning. In this work it was considered the Brazilian standard specifications (PEC, in Portuguese) for classification of cartographic bases. Results may be considered very good and showed that Cartosat-1 orthoimage presents accuracy equivalent to class B for 1:10.000 scale. The DEM presents altimetric accuracy compatible with class A of the 1:25.000 scale. Results obtained are true for this specific area/study case, but may vary in case different scenes or other studies areas are considered.