GRASS logo


d.vect.thematic - Displays thematic vectormap


display, legend


d.vect.thematic help
d.vect.thematic [-glfusm] map=string type=string column=string themetype=string themecalc=string [breakpoints=string] [layer=integer] [icon=string] [size=float] [maxsize=float] [nint=integer] colorscheme=string [pointcolor=string] [linecolor=string] [startcolor=string] [endcolor=string] [monitor=string] [where=string] [psmap=string] [group=string] [--verbose] [--quiet]


Save thematic map commands to group file for GIS Manager
Create graphic legend in x11 display monitor
Only draw fills (no outlines) for areas and points
Update color values to GRASSRGB column in attribute table
Output legend for GIS Manager (for scripting use only)
Use math notation brackets in legend
Verbose module output
Quiet module output


Vector map to display thematically
Vector map type
Options: area,point,centroid,line,boundary
Default: area
Attribute column to use for thematic display (must be numeric)
Type of thematic display
Options: graduated_colors,graduated_points,graduated_lines
Default: graduated_colors
Thematic divisions of data for display
Options: interval,std_deviation,quartiles,custom_breaks
Default: interval
Break points for custom breaks option. Separate values by spaces. (0 10 20 30 ...)
Layer to use for thematic display
Default: 1
Vector point icon for point data
Options: basic/box,basic/circle,basic/cross2,basic/diamond,basic/star,basic/cross1,basic/x
Default: basic/circle
Icon size for point data (minimum icon size/line width for graduated points/lines)
Default: 5
Maximum icon size/line width for graduated points and lines
Default: 20
Number of classes for interval theme (integer)
Default: 4
Color scheme for graduated color mapping (select 'single_color' for graduated point/line display)
Options: blue-red,red-blue,green-red,red-green,blue-green,green-blue,cyan-yellow,yellow-cyan,custom_gradient,single_color
Default: blue-red
Color for graduated points map (grass named color or R:G:B triplet). Set color scheme to single color.
Default: 255:0:0
Color for graduated lines or point/area outlines (grass named color or R:G:B triplet). Set color scheme to single color.
Default: 0:0:0
Beginning color for custom color gradient. Must be expressed as R:G:B triplet.
Default: 255:0:0
Ending color for custom color gradient. Must be expressed as R:G:B triplet
Default: 0:0:255
Select x11 display monitor for legend
Options: x0,x1,x2,x3,x4,x5,x6,none
Default: x1
WHERE conditions of SQL statement without 'where' keyword
Root for the name of psmap instruction files to be in current directory (if not set, no psmap instruction files will be created)
Name of group file where thematic map commands will be saved


d.vect.thematic - Creates thematic maps from vectors of all types and numeric attributes (stored in the data table connected to a vector map). Thematic maps can be displayed by either a graduated color scheme (for all vector types), as graduated icon sizes (for point and centroid types), or graduated line widths (for lines and boundaries with associated attributes). The user selects the vector map to be mapped and attribute column from which to derive mapping intervals, and (optionally) the layer for attribute data.

In thematic maps, the color or point size changes for each range of attribute values. Value ranges for thematic mapping can be set at regular intervals, standard deviation units on either side of the mean, quartiles, or delimited by user-defined breakpoints. User-defined breakpoints also can be entered, or piped into d.vect.thematic from standard input or other external source.

There are options to define the color scheme (graduated colors) and range of point sizes (graduated points) for thematic maps. A simple text legend is printed. Optionally, a graphic legend can be drawn in the selected display monitor. Thematic colors can be uploaded to a GRASSRGB column for later display, and thematic map display commands can be saved to a group file (*.dm) that can be opened, edited, and displayed in the GIS Manager.

When the psmap option is set to 'name', two psmap instruction files are created (in the current directory if no path is given), one for the map ('name.psmap') and one for the legend ('name_legend.psmap'). The map file also contains 'label' commands which allow to create a legend directly in the map by adding a 'vlegend' command. See the man page for more details.

(GRASS Shell Script)


The algorithm currently uses the script to calculate basic descriptive statistics needed for thematic mapping (minimum, maximum, mean, standard deviation, and quartiles).


Earthquake points with color gradient:
d.vect.thematic -l recent_earthquakes column=magnitude type=point

Earthquake points with different sizes:

d.vect.thematic -l recent_earthquakes column=magnitude type=point \
                themetype=graduated_points maxsize=15

Spearfish: differences between 'elevation.10m' and 'elevation.dem':

# random sampling of elevation points:
g.region rast=elevation.10m -p
v.random random n=200
v.db.addtable random col="el10 double precision"
# transfer elevations to attribute table of random points map:
v.what.rast random rast=elevation.10m col=elev random

# comparative sampling of second map, incl. differences:
v.sample in=random col=el10 rast=elevation.dem out=elev_sample elev_sample

# thematic map:
d.mon x0
d.vect.thematic -l elev_sample column=diff type=point


d.vect, d.vect.chart,


Michael Barton, Arizona State University, Daniel Cavelo Aros, Martin Landa, and Jachym Cepicky.

Last changed: $Date: 2007-06-02 13:46:58 -0700 (Sat, 02 Jun 2007) $

Main index - display index - Full index

© 2003-2008 GRASS Development Team