ACCUMULATED REFLECTANCE TECHNIQUE FOR SAMPLING DELIMITATION IN THE RIACHO FUNDO CREEK, LAGO PARANOÁ-DF, FROM PLANETSCOPE IMAGES

Abstract. The delimitation of sampling points is an important step to avoid unnecessary costs in water collection process and laboratory analysis. Based on the accumulated reflectance of PlanetScope imagens, it was possible to verify areas of greater spectral variability related to the presence of Optically Active Components (OAC). In order to do that, the accumulated reflectance method was used, based on multitemporal images. For that, three PlanetScope Ortho Scene Products were tested: Atmospheric Corrected for Surface Reflectance (SR), Digital Number (DN), and Top of Atmosphere Reflectance (TOA) images. SR and DN products had similar outcome, while DN product was not ideal for the purpose of this article. Even though SR and DN products were able to delimitate sampling points, they may have radiometric issues, mainly because of their near infrared values.