The invention provides a method for analyzing spatial variations in field and crop performance. The method allows analysis of the field and crop performance as a function of various treatment and/or environmental conditions. This method is an advance over the prior art in that it allows better defined, more accurate comparisons of adjacent test areas, eliminating the need for extrapolation of data and avoiding inaccuracies therefrom. Also, the more accurate comparisons allow better characterization of effects due to the environment, such as those caused by genotype by environment (G.times.E) interaction. The more accurately defined comparison units also lead to improved analysis when comparing to other data layers for non-spatial analysis. The invention also provides a system for carrying out this method. The system preferably includes a device for inputting spatially-referenced data, a memory, an output device, and a processor. The output data may be represented spatially or non-spatially. The information provided by the method and system of the invention will allow farmers to make more informed decisions regarding seed and farming inputs and practices, thereby maximizing agricultural productivity.