Problem using mapcalc?

[Philip Warner]

I've now had a look at r.mapcalc and don't seem to be able to get it to
work. I've also tried an alternate solution, which does not seem to work
either.

Using spearfish, I have:

v.to.rast input=roads output=rwrk
r.mapcalc 
comb=if(rwrk,rwrk+10,geology)

The result of this is:

CREATING SUPPORT FILES FOR comb
range: 11 15

Which is strange. It only shows the roads. No matter what I do with the
combination (eg. geology+rwrk), I always get 'no data' in the locations
where the road data is absent.

Have I misunderstood something here?

Yours in confusion,

Philip Warner



At 22:58 20/02/00 -0600, rado wrote:
>Hello Philip,
>You can transform your vector layer into the raster one. After that
>you should use r.reclass to assign some big values to your new
>raster layer. Then you can use r.mapcalc to produce another raster layer
>(geology + roads; use "+" operator). 
>Using r.reclass you can easily assign new values for "roads" to
>distinguish them from geology areas. Result is a new raster map you can
>overlay over your DEM. Since 3D tools in GRASS don't provide extensive
>query options, this hybrid raster should gives you what you expect. 
>If you want to assign proper road width, use r.buffer, before combining
>the geology and roads in r.mapcalc
..etc...
>Regards,
>
>	-Rado Bonk 
>
>On Mon, 21 Feb 2000, Philip Warner wrote:
>
>> What I want to do is combine the raster and vector (geology and roads),
>> then put the resulting map over the DEM to get a combined 3d view.
>> 

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