Geografic-Information-System/raster/r.profile/r.profile.html

<h2>DESCRIPTION</h2>

This program outputs two or four column (with <b>-g</b>) data to stdout or 
an ASCII file. The default two column output consists of cumulative profile 
length (in meters) and raster value. The optional four column output consists 
of easting, northing, cumlative profile length (m), and raster value. Profile
end or "turning" points can be set manually with the <b>profile</b>
argument or selected interactively from the GRASS monitor by setting the
<b>-i</b> flag. The profile resolution, or distance between profile
points, is obtained from the current region resolution, or can be manually
set with the <b>res</b> argument.
<p>The <b>-i</b> flag allows the user for selecting the profile from the GRASS
monitor by clicking the left mouse button along the profile; clicking the
right mouse button ends the profile.
<p>The <b>profile</b> parameter can be set to comma separated geographic
coordinates for profile line endpoints. The interactive flag (<b>-i</b>)
overrides this option. Alternatively the coordinate pairs can be piped
from stdin, one comma separated pair per line.
<p>The <b>res</b> parameter sets the distance between each profile point
(resolution). The resolution must be provided in GRASS database units (i.e.
decimal degrees for Lat Long databases and meters for UTM). By default
<em>r.profile</em> uses the resolution of the current GRASS region.
<p>The <b>null</b> parameter can optionally be set to change the character
string representing null values.

<h2>OUTPUT FORMAT</h2>

The multi column output from <em>r.profile</em> is intended for easy use in
other programs.  The output can be piped (|) directly into other programs or
saved to a file for later use. Output with geographic coordinates (<em>-g</em>)
is compatible with <em><a href="v.in.ascii.html">v.in.ascii</a></em> and can 
be piped direcly into this program.

<div class="code"><pre>
r.profile -ig input=elev.rast | v.in.ascii output=elev.profile separator=space
</pre></div>

The 2 column output is compatible with most plotting programs.
<p>The optional RGB output provides the associated GRASS colour value for
each profile point.

<h2>EXAMPLES</h2>

<b>Example 1</b><br>
Extract a profile with coordinates provided on the command line:

<div class="code"><pre>
r.profile input=elev.rast output=profile.pts profile=562517,7779433,562984,7779533,563875,7779800
</pre></div>
This will extract a profile along the track defined by the three coordinate
pairs.
<p><br>


<b>Example 2</b><br>
Extract a profile by interactively selecting the profile route from the GRASS
monitor:

<div class="code"><pre>
r.profile -i input=elev.rast output=profile.pts
</pre></div>
Use the left mouse button to select the profile route in the GRASS monitor. Use the 
right mouse button to end the profile.
<p><br>


<b>Example 3</b><br>
Extract a profile with coordinates provided from standard input or an external file:
<p>First create a points file with <em><a href="d.where.html">d.where</a></em>

<div class="code"><pre>
d.where > saved.points
</pre></div>

Then pipe the points file into r.profile

<div class="code"><pre>
cat saved.points | r.profile input=elev.rast output=profile.pts
</pre></div>

The advantage of this method is that the same profile points can be piped into
different GRASS rasters by changing the input parameter. 
<p>With this method the coordinates must be given as space or tab separated easting
and northing. Labels after these values are ignored.
<p>Another example using d.where:

<div class="code"><pre>
d.where | r.profile elevation.dem
</pre></div>

<p><br>


<b>Example 4</b><br>
Pipe coordinates into r.profile
<div class="code"><pre>
r.profile elevation.dem res=1000 &lt;&lt; EOF
 591243,4926344
 592509,4922156
 594100,4920793
 599910,4919365
 602929,4919235
 604844,4918391
 606468,4917190
 607766,4915664
EOF
</pre></div>


<h2>NOTES</h2>

The profile resolution is measured exactly from the supplied end or
"turning" point along the profile. The end of a profile segment will be an
exact multiple of the profile resolution and will therefore not always match
the end point coordinates entered for the segmanet.

<p>To extract the numbers in scripts, following parameters can be used:
<div class="code"><pre>
r.profile input=dgm12.5 profile=3570631,5763556 2>/dev/null
</pre></div>

This filters out the everything except the numbers.

<h2>SEE ALSO</h2>

<em>
<a href="v.in.ascii.html">v.in.ascii</a>,
<a href="d.where.html">d.where</a>,
<a href="d.profile.html">d.profile</a>,
<a href="r.what.html">r.what</a>,
<a href="r.transect.html">r.transect</a>,
<a href="wxGUI.html">wxGUI profile tool</a>
</em>

<h2>AUTHOR</h2>
<a href="mailto:bcovill@tekmap.ns.ca">Bob Covill</a>

<p><i>Last changed: $Date$</i>