Dear Tom,
my best acknowledgment for the Ecogrid challenging initiative.
I guess the main limitation will be "time" and this is related to the  
size of grids.
What is the extent of the grids ?
What tool you plan to use for point 1. Overlay some point data and  
get the values of grids ?

On a more theoretical basis,
"distribution models should rely upon data that covers the whole  
extent of the distribution of the biota under examination"

Please consider forest data from
http://forest.jrc.ec.europa.eu/climate-change
as supplementary predictors variables within an European biodiversity  
and nature conservation application.

Cheers
Stefano


________________________________

Stefano Casalegno, Ph.D.

via Greppi 16, 21021 Angera - Italy
email: stefano@casalegno.net
web: http://www.casalegno.net/stefano
________________________________


On Dec 13, 2009, at 6:29 PM, Tomislav Hengl wrote:

>
> Dear R-sig-geo,
>
> As a part of our project (EcoGRID.nl) we have prepared some 60  
> thematic grids that we use as auxiliary predictors for species  
> distribution modeling. At this stage, we would like to put the  
> gridded maps (50/100 m base resolution) into some efficient  
> sharable geo-database.
>
> We will most probably put the data into the NetCDF format (http:// 
> www.unidata.ucar.edu/software/netcdf/) because it can handle any- 
> dimensional array data, and because it has been in continuous  
> development and widespread use for many years. NetCDF grids can be  
> read relatively easy into R using the RNetCDF package (e.g. http:// 
> spatial-analyst.net/DATA/readNCDF.zip). Another alternative is to  
> use PostGIS WKT Raster format (http://trac.osgeo.org/postgis/wiki/ 
> WKTRaster), but this seems to be still rather experimental (?).
>
> Once we put the grids into NetCDF format. We plan to install  
> OPeNDAP (http://www.opendap.org) server on top to make the files  
> accessible through the web; then Geoserver (http:// 
> www.geoserver.org) or UMN Mapserver (http://mapserver.org) to feed  
> a WMS from NetCDF files (raster data). Finally, we plan to add a  
> simple OpenLayers interface on top of that (Geoserver has it built  
> in) to allow direct browsing of the data and metadata (e.g. such as  
> this one: http://africamap.harvard.edu/)
>
> Just to be clear, we want to put the data on a server because we  
> would like to run a number of operations directly on the server  
> (via rgdal?):
>
> 1. Overlay some point data and get the values of grids (without a  
> need to download the grids locally);
> 2. Subset/mask and resample gridded data of interest (for a given  
> bounding box and proj4 string; again without a need to download the  
> data locally);
> 3. Upscale the grids from 100 m to 250, 500 m and 1 km resolution  
> (then download the upscaled grids).
> 4. Write/upload new grids to the database (e.g. using WebDAV).
> 5. Browse the grids (and metadata) via the OpenLayers.
>
> These are only our wishes of course. We do not know if all this is  
> really possible with the current software.
>
> Any examples or comments/suggestions/experiences are welcome  
> (before we start installing and testing the functionality).
>
> Thanx!
>
> Tomislav Hengl and Lourens Veen
>
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>






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