For just about every GIS and GPS project I’ve worked on, one of the essential ingredients is a polygon that defines the boundary of the study area. I quickly learned that this is the best place to begin when gathering data for a new project.Why Do You Need a Study Area Polygon?
I can think of three good reasons why you need a study area polygon:[red_tick_list width=”100%”]
- Use it as the cookie-cutter shape to clip all of your other project data down to size.
- Know the area and perimeter distance of your study area.
- Provides a manageable extent to work with for a new GPS data collection project so your mobile map has more than just a white screen zoomed out to the extent of the coordinate system.
How to Create a Study Area Polygon
If your study area follows political boundaries such as a county, country, or census tract, then all you have to do is select the boundary and export it to a new feature class. For more fine tuned boundaries, you will probably have to use the ArcGIS for Desktop editing tools to specify exact coordinates, follow land features, and do whatever is required to define your polygon.
I discovered a way to define a general study area polygon that requires no editing whatsoever. Is it quick? Yes. Is it crude? Yes. Will it work for every situation? Probably not. Whether it works for your current GIS project, or not, is for your to decide. Either way, it’s a good trick to have in your GIS arsenal.