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

[Charles Novaes de Santana]

Dear Wilfried,

Thank you very much for your answer.

Our environmental data is in NCDF format, that we have downloaded
here: http://www.esrl.noaa.gov/psd/data/gridded/data.UDel_AirT_Precip.html

Our biotic data is in ASCII format, but we can try to convert them to
some raster format.

Thank you again, best regards!

Charles

On Wed, Dec 8, 2010 at 7:12 AM, Wilfried Thuiller
<wilfried.thuiller at ujf-grenoble.fr> wrote:
> Dear Charles,
> Do not too much the interpolations techniques. In which format are your
> data? Are they originally ArcGIS raster or grid data?
> If yes, better practice to use the raster package with the extract
> function.
> Else, I guess your approach is probably the best one.
> Best
> Wilfried
>
> Le 7 déc. 2010 à 21:22, Charles Novaes de Santana a écrit :
>
> 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
> everything!
>
> 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,
>
> Charles
>
> --
> 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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>
> --------------------------
> Dr. Wilfried Thuiller
> Laboratoire d'Ecologie Alpine, UMR CNRS 5553
> Université Joseph Fourier
> BP53, 38041 Grenoble cedex 9, France
> tel: +33 (0)4 76 51 44 97
> fax: +33 (0)4 76 51 42 79
> Email: wilfried.thuiller at ujf-grenoble.fr
> Home page: http://www.will.chez-alice.fr
> Website: http://www-leca.ujf-grenoble.fr/equipes/tde.htm
>
> FP6 European MACIS project: http://www.macis-project.net
> FP6 European EcoChange project: http://www.ecochange-project.eu
>
>
>
>
>



-- 
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