[GRASS-user] Re: Duplication of lines in output of r.profile.

Marcello Gorini gorini at gmail.com
Tue Apr 5 21:35:20 EDT 2011


Dear all,

I solved it using:

> d.where > map_profile

instead of:

> r.profile -ig input=map output=map_profile

The only problem is that I can't see the points while I am digitizing. Also,
it demands another line of code to get the actual topographic profile since
d.where only gets the coordinates, instead of sampling the raster.
Still don't know why the method with r.profile doesn't work right though. If
anybody does, I would be glad to "hear".

Thanks,
Marcello.


Marcello Gorini wrote:
> 
> Dear all,
> 
> My problem (a very common one) is that I want to digitize a profile and
> then sample other maps using the extracted coordinates. In order to do so,
> I tried the following;
> 
>>r.profile -ig input=map output=map_profile 
> 
> With that, I managed to digitize the profile and to get the following file
> (a piece of it):
> 
> -8063204.166667 4311231.250000 0.000000 -3769.528809
> -8062653.139926 4312065.737586 1000.000000 -3768.805176
> -8062102.113186 4312900.225172 2000.000000 -3768.805176
> -8061551.086445 4313734.712758 3000.000000 -3767.810791
> -8061000.059705 4314569.200344 4000.000000 -3764.308105
> -8060449.032965 4315403.687930 5000.000000 -3764.054199
> -8059898.006224 4316238.175517 6000.000000 -3763.437500
> -8059346.979484 4317072.663103 7000.000000 -3760.115723
> -8058795.952743 4317907.150689 8000.000000 -3759.792236
> -8058244.926003 4318741.638275 9000.000000 -3758.425537
> 
> Which is correct. I have eastings, northings, distance (which increases in
> steps equal to the resolution of 1000 meters) and then the sampled depth.
> 
> Ok, but the problem appears when I try to use this profile to sample
> another map... 
> 
>>cat map_profile | r.profile -g input=another_map
output=another_map_profile
> 
> .... the following happens:
> 
> -8063204.166667 4311231.250000 0.000000 8
> -8062653.139927 4312065.737586 1000.000000 8
> -8062653.139926 4312065.737586 1000.000000 8
> -8062102.113186 4312900.225172 2000.000000 8
> -8061551.086446 4313734.712758 3000.000000 8
> -8061551.086445 4313734.712758 3000.000000 8
> -8061000.059705 4314569.200344 4000.000000 8
> -8060449.032965 4315403.687930 4999.999999 8
> -8059898.006225 4316238.175516 5999.999999 8
> -8059898.006224 4316238.175517 6000.000000 8
> -8059346.979484 4317072.663103 7000.000000 8
> -8058795.952744 4317907.150689 8000.000000 8
> -8058795.952743 4317907.150689 8000.000000 8
> 
> I get many duplicated lines, some of which are not exactly duplicated, but
> displace the coordinates by a very small distance, affecting also the
> distance. The 8 in the last column is correct, don't worry.
> 
> Any ideas about what might be happening?
> 
> I thank you all very much in advance for any help.
> 
> Best regards,
> Marcello.
> 


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