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<title>GRASS GIS: d.profile</title>
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<h2>NAME</h2>
<em><b>d.profile</b></em> - Interactive profile plotting utility with optional output.
<h2>KEYWORDS</h2>
display
<h2>SYNOPSIS</h2>
<b>d.profile</b><br>
<b>d.profile help</b><br>
<b>d.profile</b> <b>rast</b>=<em>string</em> [<b>drast</b>=<em>string</em>] [<b>plotfile</b>=<em>string</em>] [--<b>verbose</b>] [--<b>quiet</b>]
<h3>Parameters:</h3>
<DL>
<DT><b>rast</b>=<em>string</em></DT>
<DD>Raster map to be profiled</DD>
<DT><b>drast</b>=<em>string</em></DT>
<DD>Optional display raster</DD>
<DT><b>plotfile</b>=<em>string</em></DT>
<DD>Output profile data to file(s) with prefix 'name'</DD>
</DL>
<H2>DESCRIPTION</H2>
This command works only interactively. It clears the entire
graphics screen and provides a graphical interaction
allowing the selection of transects for which profiles are
then generated. Input parameters can be specified on the command line
for quicker start-up.
<H2>USER PROMPTS</H2>
First, you will be presented with a prompt asking you to
choose a raster map layer to be profiled. Then you will be
prompted for an optional display raster. The optional display raster
will be shown rather than the profiled raster. This is useful
to be able to more easily see ground features, such as might be visible
in an aerial photo or satellite image. Finally, you will
be prompted for the name prefix for output file(s) containing the profile
data. This is an optional feature.
<P>
After parameters are given, the raster layer will be
displayed in the left half of the graphics monitor, and the
right half will be divided into four
frames. There will also be two frames along the top of the
monitor: a mouse-button menu frame on the left, and a
status frame on the right.
<P>
The mouse-button menu initially offers you three options:
<DL>
<DD>
Mouse Buttons: <BR>
Left: Where am I? <BR>
Middle: Mark FIRST Point of Profile Line. <BR>
Right: QUIT this. <BR>
</DL>
You may query the displayed raster map layer by indicating
points with the left mouse-button. The coordinates and
category value of each point that you indicate will be
displayed on in the status frame. If you mark the first
point of the profile line you will be presented with the
following mouse-button menu:
<DL>
<DD>
Mouse Buttons: <BR>
Left: Where am I? <BR>
Middle: Mark SECOND Point of Profile Line. <BR>
Right: QUIT this. <BR>
</DL>
Once you mark the second point of the profile line, the
profile line will be labeled (with a letter from A to D)
and displayed in one of the four display frames on the
right hand side of the screen. You will then be presented
with a third mouse-button menu:
<DL>
<DD>
Mouse Buttons: <BR>
Left: DO ANOTHER <BR>
Middle: CLEAR DISPLAY <BR>
Right: QUIT this. <BR>
</DL>
If you would like to view another profile, click on the
left mouse-button. If you would like to redisplay the
raster map layer and clear out the four profile frames,
click on the middle mouse-button. If you would like to
quit, then click on the right button.
<P>
If you selected the <B>plotfile</B> option, you will have up to
four files starting with the <EM>name</EM> and followed by a suffix
of the plot letter <EM>A, B, C,</EM> or <EM>D</EM>. The plots that
are written to these files reflect the last of each plot done with that
letter (i.e. They will match what's in the display when you quit).
<P>
The format of the plot files is not geared toward any particular software,
but should be easy to coax into a number of other programs. The first
three lines contain some header information about the plot, each prefixed
with a <TT>#</TT> sign to denote a comment. A fourth comment line describes
the data that follows. It consists of the distance (always in meters),
the cell value (in whatever units it is in), the easting in decimal format,
and the northing in decimal format.
The number of values will vary depending on the length of the profile, cell
resolution and the slope angle of the profile line. Below is an example
of a plotfile:
<P>
<TT>
# Profile A of elev.ft@snows<BR>
# From (702879.29679757, 4287317.55920185) to (702722.40973589, 4287061.72632285)<BR>
# Stats: Count = 644, Min = 2424.658936, Max = 2513.246094<BR>
# dist value east north<BR>
0.000000 2513.246094 702879.102364 4287317.516912<BR>
0.000000 2513.246094 702878.713496 4287317.118970<BR>
0.556395 2513.246094 702878.324629 4287316.721029<BR>
1.112790 2513.246094 702878.324629 4287316.323088<BR>
...<P>
</TT>
<H2>NOTES</H2>
You might notice the first two 'dist' values in the profile output above are
both zero. This is due to the fact the cell resolution for this file is
less than one meter, and so the function that calculates the distance
considers the distance between the first cell and the second to be zero.
You might also notice, the coordinates given in the header and displayed on
screen are slightly different from the first and last coordinates given in
the profile data output. This is because the profile data output finds the
eastings and northings for the center of the cells while the coordinate
transformations from mouse clicks might yield slightly different coordinates
which still fall within the same cell boundaries. The difference should
always be less than the distance between the center and any corner (not
edge!) of the cell at the resolution of the profiled raster.
<P>
Only four output plotfiles can be made. Each time a new profile is run, the
plotfile is immediately written to the file <EM>name</EM>.<EM>letter</EM>.
One can take advantage of this fact to create an unlimited number of
plotfiles simply by renaming the output files before running more profiles.
This may not always be the case, but it is at the time of this writing.
<P>
Useful enhancements to <EM>d.profile</EM> would include:
<OL>
<LI>Adding an option to display profiles using category
colors, like a bar-chart.
<LI>Allowing profile lines to be defined by a series of
points, not just two.
<LI>Allowing profiles to be saved in a file, for later
viewing by GRASS.
<LI>Allowing the user to enter profile line points by
typing coordinates.
</OL>
<H3>Perl Script to convert output to a site_list</H3>
The script below will convert the <B>plotfile</B> output to the site_list format.
It probably won't work 100% for lat/lon datasets.
<P>
<TT>
<B>#! /usr/bin/perl -w</B><BR>
# prof2sites.pl: converts the output of d.profile to a site_list
<P>
<B>my</B> (<EM>$dist</EM>, <EM>$elev</EM>, <EM>$east</EM>, <EM>$north</EM>);
<P>
<B>while</B> (<<B>STDIN</B>>)<BR>
{<BR>
<B>if</B> (m/^#/)<BR>
{<BR>
<B>print</B> "<EM>$_</EM>";<BR>
}<BR>
<B>else</B><BR>
{<BR>
<B>chomp</B>;<BR>
(<EM>$dist</EM>, <EM>$elev</EM>, <EM>$east</EM>, <EM>$north</EM>) = <B>split</B> / /;<BR>
<B>print</B> "<EM>$east</EM>|<EM>$north</EM>|<EM>$elev</EM>|#1 \%<EM>$dist</EM> \@Profile\n";<BR>
}<BR>
}<BR>
</TT>
<H2>BUGS</H2>
None known.
<H2>AUTHOR</H2>
Dave Johnson
<BR> DBA Systems, Inc. <BR>
10560 Arrowhead Drive <BR>
Fairfax, Virginia 22030
<P>
Modified by Eric G. Miller for profile output, support of
floating point rasters, and optional display raster (02-Dec-2000).
<p><i>Last changed: $Date: 2003-04-11 17:25:34 +0200 (Fri, 11 Apr 2003) $</i>
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