[GRASS-dev] gis.m: cannot get profile from profile tool

[Michael Barton]

Eric,

It sounds like you are doing this correctly. I think in the version you are
using (check the tooltips), the 1st button on the left sets the raster you
want to profile. In that version, it uses r.info to set the elevation range.
A problem with this is that it can only determine the total range for the
entire map, which may be much greater than the range of the area you are
profiling. This is changed in the version I just committed today. The new
version uses r.univar, which honors the displayed region in calculating
elevation range. The elevation range is used to set the vertical scale, and
the conversion between elevation units and screen units.

The second button from the left lets you draw a transect line to profile.

The third button runs r.profile twice. The first time it simply get's the
max distance along the line reported by r.profile and stores it to the
variable cumdist (cumulative distance). It then uses this to value to set
the horizontal scale and the conversion between horizontal map units and
screen units. This is necessary to deal with latlon regions.

It then runs r.profile again to generate the actual profile values, as a
list of distance, elevation. These are converted to screen values and
plotted to the profile graph. This was having some issues with negative
values, giving unexpected results. I also fixed that today.

So I'm not sure what the problem is for you. You might run r.profile on the
same set of end coordinates and see what it produces. If you have negative
elevation values, it might be problematic in the version you have. If
r.profile is choking for some reason, that would also be a cause.

If you want to try out the new one, simply use the web access to the cvs, go
to grass6/gui/tcltk/gis.m/profile.tcl and download it. Then move it into
your $GISBASE/etc/gm folder. It's just a text file, so it should not be a
problem.

Michael


 
__________________________________________
Michael Barton, Professor of Anthropology
School of Human Evolution & Social Change
Center for Social Dynamics & Complexity
Arizona State University

phone: 480-965-6213
fax: 480-965-7671
www: http://www.public.asu.edu/~cmbarton



> From: "Patton, Eric" <epatton at nrcan.gc.ca>
> Date: Mon, 31 Jul 2006 23:23:45 -0300
> To: 'Michael Barton ' <michael.barton at asu.edu>, 'Moritz Lennert '
> <mlennert at club.worldonline.be>
> Cc: ''Grass Developers List ' ' <grass-dev at grass.itc.it>, 'Markus Neteler '
> <neteler at itc.it>
> Subject: RE: [GRASS-dev] gis.m: cannot get profile from profile tool
> 
> Michael,
> 
> I'm confused; I selected a raster via the first button from the left on the
> profiling GUI (See the image on my ftp site); in the bottom left corner of
> the profiling GUI, the text reads "Profile for CheticampAll_Aug2005_10m"
> (the bathymetry raster I'm profiling.)
> 
> I'm at home now so I can't use Grass until tomorrow morning, but just to
> make sure I'm using it correctly, you click the first button on the left to
> load a raster to profile, the second to draw a profile in the profile
> window, and the third to render the profile graph?
> 
> ~ Eric.
> 
> -----Original Message-----
> From: Michael Barton
> To: Patton, Eric; Moritz Lennert
> Cc: 'Grass Developers List '; Markus Neteler
> Sent: 7/31/2006 3:17 PM
> Subject: Re: [GRASS-dev] gis.m: cannot get profile from profile tool
> 
> Eric,
> 
> You failed to select a raster map to profile.
> 
> I just committed an update which does a better job of trapping this kind
> of
> error and giving you a more meaningful error message. I also made the
> profiler default to the currently selected raster map to profile and
> also
> found a way of making the elevation ranges calculated within the
> currently
> displayed region, using r.univar. The primary drawback of this is that
> it is
> a bit slow to get started with enormous maps.
> 
> Michael
> __________________________________________
> Michael Barton, Professor of Anthropology
> School of Human Evolution & Social Change
> Center for Social Dynamics and Complexity
> Arizona State University
> 
> phone: 480-965-6213
> fax: 480-965-7671
> www: http://www.public.asu.edu/~cmbarton
> 
> 
>> From: "Patton, Eric" <epatton at nrcan.gc.ca>
>> Date: Mon, 31 Jul 2006 12:52:01 -0300
>> To: 'Moritz Lennert ' <mlennert at club.worldonline.be>, 'Michael Barton
> '
>> <michael.barton at asu.edu>
>> Cc: 'Grass Developers List ' <grass-dev at grass.itc.it>
>> Subject: RE: [GRASS-dev] gis.m: cannot get profile from profile tool
>> 
>> Hi guys,
>> 
>> I tried the porfiling tool with July 31 cvs, and I can't get it to
> work. The
>> y-axis gets assigned correct values for the profile I've drawn, but no
> lines
>> get drawn in the profile window. A tcltk window reports "Error: can't
> read
>> "cumdist": no such variable"
>> 
>> You can view the output on my ftp site:
>> 
>> ftp://agc.bio.ns.ca/outgoing/Patton/Grass/Bug%20Reports/
>> 
>> ~ Eric.
>> 
>> 
>> -----Original Message-----
>> From: grass-dev-bounces at grass.itc.it
>> To: Michael Barton
>> Cc: Grass Developers List
>> Sent: 7/27/2006 2:33 AM
>> Subject: Re: [GRASS-dev] gis.m: cannot get profile from profile tool
>> 
>> Michael Barton wrote:
>>> Hi Moritz,
>>> 
>>> Did you select a raster to profile?
>> 
>> Yes, as you can see in the screenshot, it says in the bottom left:
>> "Profile for srtm_be".
>> 
>> 
>>> Third button from the left on the
>>> profiler toolbar.
>>> Rather like d.profile, the profiler differentiates between
>>> a map you use as a background to the profiling line (what is shown in
>> the
>>> map display) and the map that you actually use to compute profile
>> values.
>> 
>> 
>> I understand that, but I still don't get a profile. Actually, I
>> sometimes do not even get the straight blue line you see in the
>> screenshot (http://moritz.homelinux.org/grass/gism_profile.png), just
> an
>> 
>> empty graph.
>> 
>> The min and max of the heights on the y axis seem correct, though.
>> 
>> Moritz
>> 
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>