[R] produce a map in ARCGIS from a GAM output

Barry Rowlingson b.rowlingson at lancaster.ac.uk
Fri Apr 12 15:15:24 CEST 2013

On Fri, Apr 12, 2013 at 10:37 AM, Lauria, Valentina
<valentina.lauria at nuigalway.ie> wrote:
> Hi,
> I am trying to predict the habitat suitability of lobster with GAMs. I need to produce a map in ArcGis of the predicted densities. I did some search and the function predict.gam seems to do the job.
> Is this the right way to do it? when you apply the function you get the predicted values (different from your input data points) but I do not understand what is the procedure with the spatial coordinates, I mean what lat and long have the new points? Can I use the same ones of my observations?

 I suspect you'll get a better response if you:

 a) ask on R-sig-geo, the mailing list for all things R and mappy
 b) try and ask with a reproducible example - it doesn't have to be
your data, but something similar, and small, and that we can run to
get a better idea of your problem. Show us how you are running
predict.gam, at least, and what your data looks like.

To get data from R into ArcGIS you probably want to either use the
raster package to create a grid of values, or the rgdal package to
create a shapefile of point locations and estimates. Exactly how you
get that from your predict.gam results is a bit guesswork until we
know a bit more about how you are running predict.gam....


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