Answer: GIS (GEOGRAPHICAL INFORMATION SYSTEM)
The GIS is a technique that is designed to capture the spatial and geographical data. It allows the analyses, store and manipulate the data obtained after the survey. This system can be used for surveying the entire forest area. The features of the area are obtained as points, lines and raster images. The water bodies and trees can be observed as a typical colored image. Therefore, gives idea about the total area covered by the water body and the vegetation. It will tell if the vegetation has been removed by the human intervention. Hence, is useful method to track the health of the amazon rain forest.