Identificação semiautomática de lineamentos morfoestruturais no norte da Bacia Paraíba, PB

Morphostructural lineaments are linear features in terrain surface evidenced by morphological elements such as ridges of hills and drainage lines. In our study area, at the northern Paraíba Basin, previous studies describe these features as possibly associated with geological and tectonic structures, as faults and folds. The mapping of lineaments has been eased by several techniques and remote sensing data. In the present work we evaluated the potential of TecLines, a semi-automated Matlab-based toolbox for lineament analysis from remote sensing data. This algorithm was tested on two different versions of the digital elevation model (DEM) acquired by the Shuttle Radar Topography Mission (SRTM). Results were evaluated through visual interpretation, rose diagrams and descriptive statistics. Using a 1:100.000 map of manually extracted set of lineaments as reference, the digital approach showed better performance in areas of the crystalline basement, where abundant lineaments are evident in relief. In the sedimentary areas, otherwise, the gentle topographic expression of the occasional lineaments limited their extraction from DEM. Despite the potentially useful sets of experimental results, sensitivity of the automated extraction was shown to be directly dependent of the operation parameters, indicating the convenience of trial-and-error determination of optimal levels for accuracy according to data and relief conditions. According to the prevailing nature (and so the topographic expression) of the lineament features in different types of terrain (e.g., crystalline or sedimentary) of complex landscapes, we recommend a stratified application of automated lineament extraction, with parameters selected in customized developments.