Comparação dos programas TC2DFTPL e TCFOUR no cálculo da correção de terreno para o Estado do Rio Grande do Sul

The terrain correction is one of gravimetric reductions applied to gravitational acceleration value. The purpose of this study was compare the performance of TC2DFTPL and TCFOUR programs to check significant differences between these programs in calculating terrain correction for Rio Grande do Sul State. The results obtained for the TC2DFTPL and TCFOUR programs were similar. However, the TCFOUR program presents border effect, unlike TC2DFTPL program. It was noted a mismatch between the statistics results to maximum and minimum values obtained for terrain correction, calculated by both programs using the SRTM and ASTER DTMs with resolutions of 5 km, 2 km and 1 km. It was conclude that this difference is due to the need to partition the study area for higher resolutions and also the altimetric differences between two DTMs; more evident in the region of higher altitudes, such as the Serra Geral region.