[Biomod-commits] BIOMOD EXAMPLE

[Joseph Maina]

Hi Wilfred,

I am following up on this thread..
http://lists.r-forge.r-project.org/pipermail/biomod-commits/2009-September/000019.html

what is still not clear to me is, from which data will the
pseudo-absences/background data be selected? in the above thread you
say:  "When you set the NbRepPA,  two selections
of pseudo-absence will be carried out. This means than  1000
pseudo-absences will be drawn from the original dataset to build the
presence-absence matrix. That will done twice with the algorithm you
selected (random, or other)."  Is this 'original dataset' the
occurrence .csv file that is loaded at the start? can I define a
'geographical space' (my study area) from where BIOMOD
could extract the pseudo-absences/background data? if not what spatial
extent does BIOMOD use to select pseudo-absences? I have followed the
manual and  I am at a point where I have run the Model function using
the occurrence .csv file; up to now I have not loaded any raster data
set and wondering how BIOMOD extracts background points/pseudoabsences
without prior info on the study extent..and wondering how I can define
this upfront.

Thanks,
Joseph