Samuel Dias Santos; Maria Otávia Silva Crepaldi; Leonardo Thompson da Silva; Allívia Rouse Carregosa Rabbani
The results also show that the applica ion of mixed vectorizaion to the ALOS-PALSAR DEM significantly improved accuracy, resul ing in only slight varia ions, ranging from 3.13% for number of drainage channels to 0% for sinuosity index. This approach led to significant improvements in the parameters and variables related to watershed perimeter, with varia ions in circularity index (Ci) and compactness coe ficient (Cc) falling from -47.76% and 37.05%, respec ively, to 0.47% and -0.23%, respec ively.
CONCLUSION The findings show that the accuracy of the automa ic vectorizaion and morphometric characteriza ion of drainage networks is in luenced by various factors. The DEM that produced the most consistent results was the ALOS-PALSAR DEM. This shows that, when comparing DEMs generated using similar methodologies, the higher the spa ial resolu ion of the DEM, the better the accuracy. Moreover, the DEMs obtained by ac ive radar signal imaging showed better accuracy in rela ion to the ASTER-GDEM, generated from stereoscopic pairs of op ical images created from passive satellite sensors. The level of detail obtained by automa ic vectoriza ion can be brought closer to that of manual vectoriza ion by adjus ing the value inputted into the Threshold field of the Channel network and drainage basin tool, reducing varia ions between the model and the on-ground hydrographic network. Manual vectoriza ion is the best, or probably the only, op ion for following circumstance: studies that demand a high level of accuracy; mapping of small watersheds or subwatersheds with few watercourses; and the produc ion of administra ive and criminal technical case reports, where accuracy may be called into ques ion and inaccuracy may lead to the incorrect applica ion of the law, for example by calcula ing a lower number of watercourses and area of permanent preserva ion areas.
