[Biomod-commits] Environmental and biotic data at different locations

Charles Novaes de Santana charles.santana at gmail.com
Tue Dec 7 21:22:13 CET 2010

Dear all,

First of all, I would like to say "Congratulations" to all the
developers of BIOMOD. It is a GREAT tool and I can not imagine the
hard work you need to mantain it working so nice! Thank your for

I am just starting to use Biomod, and I have a question that maybe is
a tipical "newbie" question :)

My biotic data (presence of species) are not at the same grid that my
environmental data (temperature and precipitation). And my
environmental data are at a regular grid while my biotic data are at
points irregularly spaced.

I think the best thing to do in this case is to make an interpolation
of my environmental data to find the values of temperature and
precipitation at the same grid points of my biotic data. To do it, I
am using the function "interp" from the package "akima". Am I correct?
Is ther another option?

Here, just an example similar of my case: environmental data at a
regular gridpoint. Biotic data at points irregularly spaced.

environmental$lat <- c(2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0, 6.5,
7.0, 7.5, 8.0)
environmental$lon <- c(-38.5, -38.0, -37.5, -37.0, -36.5, -36.0,
-35.5, -35.0, -34.5, -34.0,-33.5, -33.0, -32.5, -32.0, -31.5, -31.0)
biotic$lat <- c(4.222, 4.250, 4.34, 4.7, 4.71, 4.77, 4.811, 4.99)
biotic$lon<- c(-35.1, -34.8, -34.7, -34.4, -34.38, -34.21, -33.23, -32.77)

biotic$temp <- interp (environmental$lon, environmental$lat,
environmental$temp, biotic$lon, biotic$lat)

Thank you in advance for any help!

best regards,


Um axé! :)

Charles Novaes de Santana
PhD student - Global Change
Laboratorio Internacional de Cambio Global
Department of Global Change Research
Instituto Mediterráneo de Estudios Avanzados(CSIC/UIB)
Calle Miquel Marques 21, 07006
Esporles - Islas Baleares - España

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