DESCRIPTION
d.vect.thematic draws thematic choropleth vector maps based
on an attribute column or an expression involving several columns.
It takes a list of class breaks (excluding the minimum and maximum
values) and a list of colors to apply to the classes (has to be the
number of class breaks + 1).
Instead of a list of class breaks, the user can also chose a
classification algorithm and a number of classes
(nbclasses). See the
v.class for more information on
these different algorithms.
Important note: The module currently supports only area
vector type. For displaying thematic choropleth vector maps of other
types (points, lines) can be
used d.vect.thematic2
available in AddOns
via g.extension.
NOTES
The -l flag instructs the module to print legend information
(class min | class max | number of observations in class |
color) to standard output for futher use in graphical software.
When combined with the -e flag, the legend information will
be extended with some additional statistical information. If the
-n flag is set, the module will only print the legend
information without drawing the map. If the user gives a
legendfile, the module will
write d.graph instructions for
painting a legend into that file.
EXAMPLE
d.vect.thematic -l map=communes3 column=pop \
breaks=111393.250000,222785.500000,334177.750000 \
colors=255:0:0,0:255:0,0:0:255,0,0,0
The following example uses a calculated attribute (density =
pop/area) and the standard deviation algorithm to calculate class
breaks for 5 classes:
d.vect.thematic -l map=communes2 column=pop/area algorithm=std \
nbclasses=5 colors=0:0:255,50:100:255,255:100:50,255:0:0,156:0:0
SEE ALSO
v.class,
d.vect,
d.graph,
v.univar
Check also Python module from
AddOns: d.vect.thematic2
AUTHOR
Moritz Lennert
Last changed: $Date$