topic Re: Determining contribution of environmental variables on biodiversity in Spatial Statistics Questions

Determining contribution of environmental variables on biodiversity

AliceHughes — Sat, 30 Jul 2011 10:29:28 GMT

Hello

I am user of ArcEditor 9.2. I have raster layers of biodiversity of 171 species over Southeast Asia and a set of environmental variables. I wish to determine the input of each independent variable on biodiversity -does anyone know the best way to do this in Arc?
Thanks

Alice

Re: Determining contribution of environmental variables on biodiversity

ChrisBater — Wed, 03 Aug 2011 19:40:30 GMT

I wouldn't do this in Arc. I would generate a sample of (point) locations, get the values of the your different surfaces for each location, then use a proper stats package like R or SPSS to determine the importance of your different predictor variables on biodiversity. You could use something like Akaike's information criterion to select the best subset of predictor variables to narrow things down a bit.

Re: Determining contribution of environmental variables on biodiversity

LaurenRosenshein — Wed, 03 Aug 2011 21:13:48 GMT

Hi Alice,

That's a great question. We do have some great tools for doing regression analysis inside of ArcGIS, although they were not implemented until ArcGIS 9.3. Whether you have access to a later version of ArcGIS or not, there are tons of resources to help you get started with regression analysis, which you can find here: http://esriurl.com/spatialstats. You may want to start with the Training Seminar called Regression Analysis Basics. There is also an article that we wrote recently called Finding a Meaningful Model which talks about some of the ins and outs of finding a good model.

You will need to sample your data (using any variety of methods, including the Sample tool) to perform your regression analysis (whether you perform your analysis in ArcGIS or another package), which is important with raster data because of the spatial autocorrelation between the cells.

There are tons of different software packages that you can use to do this type of regression analysis, so even if you are unable to get access to ArcGIS 9.3 or later and need to do your regression analysis in another package, I hope that these resources help you with your analysis!