In reply to Lindsay.

The key is that in a uniform point process, the EXPECTED number of points depends on the AREA of the region. In fact, the formula is just Expected=I*A, where I is the intensity (=density) of the uniform process and A is the area of the region. So if you have a map, you can count the number of points in each region and divide by the area of the region. Then you can use the chi-square statistic to test whether the set of observed densities are uniform.