The problem below is actually in reference to determining the location of a unknown gamma radiation source. However, I believe the solution lies with relatively simple calculus. First, the equation that defines the relationship between the radiation exposure rate and the distance from the source is defined by: y = k / x^2 Where y is the dose rate, x is the distance from the source, and k is a constant which may vary depending on the specific situation and source. Next, this needs to be applied in three dimensions (x,y,z). So I believe it needs to be rotated around the y-axis to form a surface of revolution. If I remember correctly, the equation for such a surface should look something like: x^2 + z^2 = 1 / y^2 On this curve your distance from the y-axis on the x-z plane would be equivalent to your distance frlom the radiation source, and the y-coord corresponding to each (x,z) would be the dose rate at that distance. Think of it this way. At point (x,y,z) x and z are like latitude and longitude while y is the radiation dose rate. This curve could be rotated around any line parallel to the y-axis, so the highest y reading would not always be at x-z point (0,0). Here is what I am trying to accomplish: If I have multiple (x,y,z) points where x and z are latitude and longitude (or just points on the x-z plane measured in feet) and y is the radiation rate, I want to be able to locate the highest y-reading on the x-z plane. In other words, if I know a radiation reading at two or three points and the latitude and longitude at those points, I want to be able to locate latitude and longitude of the radiation source. Any ideas?