There are several good math exercises here. For fourth graders this is a good gateway to the metric system. Compare a yard stick to a meter stick. You can also draw a map on the board with a pretend site. Put in trees and rocks and other features in one colored chalk. Then lay a grid on top of it in another color chalk. Number and letter the grid A,B,C,D,... and so on across the top and 1,2,3,4, down the side. Have the kids locate the features by their grid numbers such as A1, A2,C3, and so on. We use many such grids and matrices in our modern world and this is a fun way to learn how they work.

For older student the survey aspect opens the door to Euclidian geometry. They can locate thing the way a surveyer does with angles and distances from a point.