ABSTRACT
This chapter discusses a Geographic Information Systems (GIS). A GIS is a software system that contains functions to perform input, storage, editing, manipulation, analysis and display of geographically located data. In 2-dimensional systems the user often models the scattered or randomly located source data into a uniform or regular data structure. The objective of the modeling step is to apply a mathematical model that best fits the physical model. Sometimes the source data needs to be queried and/or edited, and other times the model results need to be queried and/or edited. The iso-surface is a polygonized data structure which is positioned through the 3-dimensional grid where the level of the phenomenon is of equal value. The iso-surface is given its shape by forming small triangular polygons through the gridded data and then connecting these triangles together to form a 3-dimensional surface of equal value, or an iso-surface.
