Geografic-Information-System/display/d.vect/d.vect.html

<h2>DESCRIPTION</h2>

<em>d.vect</em> displays vector maps in the active frame on the
graphics monitor.

<h2>NOTES</h2>

<em>d.vect</em> can simply be used typing <tt>d.vect
map=vector_map</tt>. There are a large variety of optional parameters
which allow the user to specify vector type, colors, data fields, SQL
queries, label size and justification, etc.

<p>By default <em>d.vect</em> areas are filled with <b>fill_color</b> and 
outlined with <b>color</b>. Area outlines can be suppressed with
<div class="code"><pre>
d.vect map=vector_map color=none
</pre></div>
and areas can be made transparent with
<div class="code"><pre>
d.vect map=vector_map fill_color=none
</pre></div>

<p>In order to display attributes in the map, <b>attribute_column</b> must
be specified.

<p>Feature colors may be specified
by <em><a href="v.colors.html">v.colors</a></em> in a form of color
table or in an attribute table column containing <tt>RRR:GGG:BBB</tt>
values.

<p>A table for a vector map might look like this:

<div class="code"><pre>
db.select sql="select * from testisola"
cat|label|GRASSRGB
0|no data|255:255:255
90|FRASSILONGO|23:245:67
104|LEVICO|23:145:67
139|PERGINE VALSUGANA|223:45:237
168|SANT'ORSOLA|223:45:67
190|TENNA|123:45:67
</pre></div>

<p>To add the GRASSRGB color column, use <em><a href="v.db.addcolumn.html">v.db.addcolumn</a></em>:
<div class="code"><pre>
v.db.addcolumn map=testisola columns="GRASSRGB varchar(11)"
</pre></div>

<p>To add/change a color, use <em><a href="v.db.update.html">v.db.update</a></em>:
<div class="code"><pre>
v.db.update map=testisola column=GRASSRGB value="123:45:237" where="cat=139"
</pre></div>

<p>A much simpler method of color coding is by using the <b>-c</b> flag
which displays vector elements of like category number with a random
color.

<p>This module can use FreeType/TrueType fonts if they have already been selected with
<em><a href="d.font.html">d.font</a></em>.

<p>Parameter <b>width</b> is set by default to '0'. XDRIVER specifies the
precise behaviour for non-zero line width, but drivers have some
freedom as to how zero-width lines are handled, so they can use the
hardware's &quot;thin line&quot; drawing primitive, if it has one. A
width of zero can potentially result in significantly faster operation. On
drivers where there is no such thing as a "thin" line, the driver will
use a sensible default (which might not be the same as '1').

<h2>EXAMPLES</h2>

Spearfish examples:

<div class="code"><pre>
# display roads with category numbers:
d.vect map=roads display=shape,cat label_color=green

# display randomly colorized soils map with attributes
d.vect -c map=soils attribute_column=label

# display randomly colorized selected vectors from soils map
d.vect -c map=soils where="label='VBF'" display=shape attribute_column=label
</pre></div>

<p>3D points, 3D lines and 3D polygons colorized according to z height:
<div class="code"><pre>
g.region raster=elevation.10m
r.random input=elevation.10m n=5000 vector=random3d -d
d.mon start=x0
# display as black points
d.vect map=random3d
# display 3D points colorized according to z height
d.vect map=random3d zcolor=gyr

# 3D contour lines
r.contour input=elevation.10m output=contour20m step=20
d.vect map=contour20m zcolor=gyr

# generate 3D triangles
v.delaunay input=random3d output=random3d_del
# display 3D polygons colorized according to z height
d.vect map=random3d_del type=area zcolor=gyr
</pre></div>

<h2>SEE ALSO</h2>

<em>
  <a href="v.colors.html">v.colors</a>,
  <a href="d.erase.html">d.erase</a>,
  <a href="d.rast.html">d.rast</a>,
  <a href="v.colors.html">v.colors</a>,
  <a href="v.db.addcolumn.html">v.db.addcolumn</a>,
  <a href="v.db.update.html">v.db.update</a>
</em>
<p>
<em>
  <a href="sql.html">GRASS SQL interface</a>
</em>

<h2>AUTHORS</h2>

CERL<br>
Radim Blazek, ITC-Irst, Trento, Italy<br>
Support for color tables by Martin Landa, Czech Technical University in Prague (8/2011)<br>
and many other GRASS developers

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