You can create the model using data contained in a data.frame but then -- because you are creating a species distribution model - you still need the raster stack to actually run the prediction and make the map representing the model. And your raster stack still needs to have those environmental variables, even if you are dealing with seasonal data and time is another factor. Perhaps I'm not understanding your scenario. At any rate, the SDM vignette that comes with dismo shows you how to use randomPoints to extract the values from a raster stack to a data.frame, which you then can use to create your model. (page 26 in here: http://cran.r-project.org/web/packages/dismo/vignettes/sdm.pdf ). Is that what you are asking? Tim ---------- Date: Thu, 08 Aug 2013 20:11:22 +1000 From: Gerardo Martin <gerardommc at gmail.com> To: r-sig-geo at r-project.org Subject: [R-sig-Geo] data.frame methods for maxlike and maxent Message-ID: <52036ECA.6010200 at gmail.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Hi all. I'm trying to implement some species distribution models with my data sets. Because of the nature of the organisms i'm working with I need specifically to fit models with data contained in a data.frame instead of providing the x,y locations to be sampled from a rasterStack. Firstly i've found one way of doing it with dismo's maxent implementation, by providing a vector with 1's ans 0's, 0 values correspond to values extracted with randomPonints. However, I haven't found a way of providing the data.fame as background data, instead of pseudoabsences as described. Secondly, I also want to fit a maxlike model, but haven't found if there's a data.frame method. Like I said, I can't do it with the traditional rasterStack method, because the information to fit the model is seasonal. Any help is really appreciated. Regards Gerardo _______________________________________________ R-sig-Geo mailing list R-sig-Geo at r-project.org https://stat.ethz.ch/mailman/listinfo/r-sig-geo End of R-sig-Geo Digest, Vol 120, Issue 8
data.frame methods for maxlike and maxent
1 message · Tim Howard