[GRASS-user] Re: Import global maps (Ascii, png or KLM) from riverthreat.net

[Micha Silver]

On Mon, 2011-08-15 at 10:24 +0200, Johannes Radinger wrote:
> Hello again!
> 
> Just to follow up my last weeks question:
> Is there anyone who can help me how to import a map from
> riverthreat.net? What are the appropriate settings of the
> coordinate system? and how do I have to import the raster
> maps? For more info just see email below.
> 

I tried with the ASCII formatted data and it works fine using the GRASS
r.in.arc module. Here are the steps:
Create a GRASS location based on the EPSG:4326 coordinate reference
system, and set its region to the whole world, with resolution 0.5 deg:

 g.region e=180 w=-180 n=90 s=-90 res=0.5 -p

Download the ASCII file. I had to make one small change in the ARC/Info
headers: the NOVALUE number should be an integer, so just change it to
-9999 (instead of -9999.00000).
Now:

r.in.arc Pesticide_Loading.asc out=pesticide

and display the resulting raster.

--
Micha

> thank you very much
> /Johannes
> 
> 
> -------- Original-Nachricht --------
> Datum: Wed, 10 Aug 2011 12:43:42 +0200
> Von: "Johannes Radinger" <JRadinger at gmx.at>
> An: grass-user at lists.osgeo.org
> Betreff: Import global maps (Ascii, png or KLM) from riverthreat.net
> 
> Hello,
> 
> I've a question concerning the import of raster maps into grass:
> 
> On http://www.riverthreat.net/data.html it is possible to get
> worldwide data on river threats and environmental pressures. The data
> are provided either as images (png), ascii files or Google-Earth KLM files
> with a resolution of 30 seconds (0.5 degrees).
> 
> I'd like to import some of these maps into grass gis for further analysis. Thus some questions arise: 
> 
> *Which coordinate system do I have to select so that the data are displayed correctly?
> * What is the best data format for the import? I think maybe Ascii? These files have a header like following:
> ncols   720
> nrows   360
> xllcorner   -180.000000
> yllcorner   -90
> cellsize   0.500000
> NODATA_value   -9999.000000
> 
> Maybe you can help me with the import!
> 
> Thank you very much
> Johannes
> -- 
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> 
>