[GRASSLIST:9233] Re: mapping the output of a population model

[Ian MacMillan]

Luigi, try something like:
r.mapcalc newmap= 'if (oldmap>1000,oldmap,null())'

-Ian

On Nov 28, 2005, at 1:48 PM, Luigi Ponti wrote:

> Thanks Stephan,
>
> I was able to import the ASCII text file to vector points and 
> interpolate between them.
> Also, based on a very useful but unrelated discussion, I obtained a 
> very pretty shaded relief over which I draped the interpolated raster.
>
> Now I have started clipping the region that are not of interest to the 
> analysis. To clip out what is not California, I have transformed a 
> vector layout of the state to a raster via v.to.rast, and used it as a 
> mask in v.surf.rst.
>
> How could I clip regions that have an elevation greater than a 
> particular value based on the elevation model raster?
>
> Thanks again,
>
> Luigi
>
>
>
>
>
> Stephan Holl wrote:
>
>> Hello Luigi,
>> On Mon, 21 Nov 2005 17:20:05 -0800 Luigi Ponti <lponti at infinito.it>
>> wrote:
>>
>>
>>> Thanks Ian and Hamish,
>>>
>>> I was eventually able to fix the problem by downloading a 
>>> unprojected California layout shapefile (form <www.census.gov>) and 
>>> then
>>> importing it via v.proj in the location with the digital elevation
>>> map. Apparently the official shapefile of California layout has a
>>> wrong latitude.
>>>
>>> Next step is to connect the output table of the population model 
>>> (population densities at weather stations) to the map I have just 
>>> created. This would hopefully result in an interpolated raster.
>>>
>>> Hamish suggested the following:
>>>
>>> Load in site data with v.in.ascii & interpolate between sites with
>>> v.surf.rst.
>>>
>>> According to the manual v.in.ascii uses the | separator. Is it worth
>>> to manually put the file in that format or do you think is better to
>>> convert it in a database to connect with a specific command?
>>>
>>>
>>
>> you could use the fs="," for selecting a , as a selector.
>>
>> have a look at the manual-page of v.in.ascii.
>>
>> g.manual v.in.ascii or
>>
>> v.in.ascii -h
>>
>>
>> Best
>> 	Stephan
>>
>>
>>
>>
>
>
 >
 >
What happens if a big asteroid hits Earth? Judging from realistic 
simulations involving a sledge hammer and a common laboratory frog, we 
can assume it will be pretty bad.
  - Dave Barry


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