Referencing Data to Real Locations

A GIS represents reality, it is not reality. To be useful, a GIS map must accurately represent feature locations. To determine the location of features in the real world or on a map, you need a reference system—a set of lines of known location that can be used to determine the locations of features that fall between the lines.

In a GIS, the reference systems used to determine feature locations are called coordinate systems. In this session, you will learn about different coordinate systems, how they work, and how to change the coordinate system of a map. By understanding coordinate systems, you will be able to manage your data in a way that increases the accuracy of your GIS maps and all the work you do with them.