Map overlay in G.I.S. [articol]

Abstract

Map Overlay is the process of taking two different thematic maps of the same area and overlaying them one on top of the other to form a new map layer. Map overlay can be defined as "The ability to integrate data from two sources using map over is perhaps the key GIS analysis function". Overlay analyses creates some combinations between graphic primitives from the different layers in accordance with certain imposed conditions (based on the Boolean algebra). OVERLAY operations represent the core of the GIS analyze that combines more spatial entities and offer new information, which can be accomplished with vector and raster data. These operations combine some maps by using arithmetical, relation and conditional operators’ functions or other types of functions.