AY Honors/Identifying Community Needs/Maps
From Pathfinder Wiki
Unless very sparsely populated, an area of even one square mile may be sufficient or possibly too large for this project. Choose an area that you can actually assess carefully in the time you allot with the number of people you have to do it. Then with photocopies of a map of the area define each team's "zone" for them so that there will be no unneeded overlapping and no place unchecked.
Use one of the many online mapping services, or obtain a street atlas. The point is to clearly define your target territory.