[GRASSLIST:9663] Re: Import Gridded Population of the World

[Markus Neteler]

Karl,

[ after having received offlist the data]
ok.

the problem is that GRASS by default applies
a linear color table. However, with the megacities
in Asia and elsewhere, this doesn't quite work

the solution is to apply a custom color table,
or, as a first approach, a logarithmic table

r.colors asds00gialpha1 col=grey.log
d.rast asds00gialpha1

Works :-)

Markus

On Wed, Dec 28, 2005 at 03:42:42PM +0100, Karl Broich wrote:
> Markus,
> 
> At 11:23 28.12.2005 +0100, you wrote:
> >Karl,
> >
> >did you zoom to the map?
> 
> no.
> 
> >g.region rast=gpw -p
> >
> >Then you may check the statistics (probably just the color
> >table is non-representative):
> >
> >r.univar gpw
> 
> total null and non-null cells: 5246208
> total null cells: 0
> 
> Of the non-null cells:
> ----------------------
> n: 5246208
> minimum: 0
> maximum: 5.85072e-39
> range: 5.85072e-39
> mean: 5.68089e-44
> standard deviation: 2.93343e-42
> variance: 8.60502e-84
> variation coefficient: 5163.69 %
> sum: 2.98031e-37
> 
> 
> >If everything is still zero, please let us know.
> 
> It is not exactly zero but very, very small.
> Is there something wrong with this data? How can I check this?
> 
> Just for Information: I used GRASS 6.1 CVS.
> 
> Karl
> 
> 
> 
> 
> --------------------------------------------------------------------------
> Dr.-Ing. Karl BROICH			Tel:	+49 / (0) 89 / 6004 2478
> Universität der Bundeswehr München	Fax:	+49 / (0) 89 / 6004 3858
> Institut für Wasserwesen
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> 

-- 
Markus Neteler     <neteler itc it>       http://mpa.itc.it
ITC-irst -  Centro per la Ricerca Scientifica e Tecnologica
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