There are 1091 archaeological points in my study area. I am going to find the suitability map based on the points and some other criteria such as aspect, slope, elevation, proximity to rivers and so on. But chi-square test showed some are not significant such as aspect. Then I used the chi-square number for each criterion as its weight. For example, slope has chi=226 so I supposed its is more important than elevation which has chi=100. Indeed I considered the degree of freedom to compare the criteria. I am not sure that my method is correct or not although the assessment by 30% of points (I used 70% for training phase) consistent with training. It has R2=0.98.
Is my method reliable? or is there any other method for the problem?