The objective of this paper is to present the methods developed to construct of hydrography mask of Amazon Radiography Project (RAM), as a methodology to be follow. The construction of theses masks is required because of necessity to get altimetry data from water, since the use of Synthetic Aperture Radar (SAR) doesn´t get altimetry accurate information because of the reflectance phenomenon on the water which behaves itself like a specular surface. The main of this study is to reduce operator subjectivity on the mask construction through of standardization of procedures. For this, first of all, a study area was chosen and the mask construct process was understood. After this, some suggestions were included in the process and then, it was possible to analyze the results. At the end, this methodology proposed earned time that before was lost on the mask construct process, showing as the most suitable in relation of available resources, precision and celerity factors.