Hi Esther, I've used the geographically weighted regression tool to do this. There's a good tutorial on this in the resources centre (search for GWR or OLS) that explains the assumptions / limitations of using correlation on spatial data (issues of spatial autocorrelation etc) and shows you how to use the tools. As far as I understand, both your datasets have to be shapefiles - it doesn't work on raster data. I used zonal tools to aggregate my raster data to zones. Hope this helps, Kate. Is there a method for doing this with nominal data, for example "habitat Type", where the habitat may be "Oak Woodland", "agriculture", etc.? I know there are other methods for determining a relationship, but I'm losing where/how you do it in ArcGIS with data layers. I thought I might be able to intersect point observations with a habitat layer, then use an attribute from the intersected habitat with the autocorrelation tool to determine if its clusterd or not, if it is, then there is a relationship between the variables. But the Auto-correlation tool also want's a numeric field. If I classify each habitat type with a number value, would that yield real results? Since in this case 2 is not 1 + 1, I think it may produce baloney. I have been getting summaries on habitat type and taking the top ranked classes, but I feel thier should be something else that is more appropriate (other than chi squared). thanks
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