GIS Week 5: Map Projections, Part 1

This week we started learning about map projections and how to re-project spatial data in ArcMap. This week's lab assignment was to display Florida counties using three different map projections, thereby illustrating the way different projections display (and distort) information differently. As you can see from the map below, where all three projections are lined up side by side, Florida's shape and orientation look slightly different depending on which coordinate system is used. More than that, sizes are affected. We used ArcMap to calculate the area for each of four counties in each map projection, and came up with three very different sets of numbers. Some parts of the state aren't affected too much, but others, specifically those farther away from a particular projection's most accurate region, vary a lot. Based on this, it's easy to see how important it is to make sure all of your data uses a consistent coordinate system before trying to do any spatial analysis.