[GRASS-user] Getting Gridded Population of the World (GPW) data into GRASS

Ben Madin lists at remoteinformation.com.au
Wed Oct 19 21:43:27 EDT 2011

G'day all,

I have tried to search for this, but the only chain I found included some off-list component, and I'm not sure what actually happened.

I have not been able to import GPW data into GRASS successfully. 

I am downloading data from http://sedac.ciesin.columbia.edu/gpw/global.jsp

I have downloaded the .bil, the ascii grid and the ESRI GRID data types for population count and population density at different resolutions and viewed them in QGIS - there was no real problem once I had changed the colourmap. It appears that there is a completely way out value in the millions range, although most of the data is less than a thousand. I have viewed the .ascii file and can see that there are plenty of values. 

for example 

> r.in.gdal -o input=/Users/benmadin/Spatial/raster/gl_gpwfe_pcount_10_bil_25/glp10ag.bil output=glp10ag
WARNING: Over-riding projection check
r.in.gdal complete. Raster map <glp10ag> created.
> r.univar glp10ag
total null and non-null cells: 29652480
total null cells: 29652480

Of the non-null cells:
n: 0
minimum: nan
maximum: nan
range: nan
mean: nan
mean of absolute values: nan
standard deviation: nan
variance: nan
variation coefficient: nan %
sum: 0

when I use r.in.gdal (or r.in.arc or r.in.bin) they all seem to work without trouble. They also work fine for gridded livestock of the world data, or worldclim data. 

> r.univar tmin1.bil
total null and non-null cells: 29652480
total null cells: 20297072

Of the non-null cells:
n: 9355408
minimum: -547
maximum: 266
range: 813
mean: -71.4324
mean of absolute values: 196.981
standard deviation: 214.727
variance: 46107.5
variation coefficient: -300.601 %
sum: -668279360

Is there anyone else who has been able to successfully import  gpw data to grass. If I wasn't able to display it in QGIS I would just give up, but there must be something going on (both my QGIS and GRASS are using the same versions of GDAL etc)



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