DESCRIPTION

d.vect.chart displays charts for GRASS vector data in the active frame on the graphics monitor.

NOTES

The charts are positioned as follows:

vector points: on point position,
vector lines: on line centers,
vector areas: on area centroids.

Bar charts are placed with their lower edge starting from the y-coordinate of the feature being symbolized, and centered with respect to the x-coordinate. The -c flag can be used to center the bar chart in both x and y directions.

The 'sizecol' parameter is proportionate to the radius.

The optional max_ref parameter accepts a list of values that represent the maximum value for each column listed in the values for the parameter columns. These values are used to create a framed bar plot if chart_type is bar (See Example 2).

EXAMPLES

Example 1

Pie-charts of monthly winter precipitation (North Carolina sample dataset):

g.region vector=nc_state -p
d.vect nc_state
d.vect.chart precip_30ynormals chart_type=pie columns=nov,dec,jan,feb -l

# show pie chart as 3D
d.erase
d.vect nc_state
d.vect.chart precip_30ynormals chart_type=pie columns=nov,dec,jan,feb -l -3

2D pie-chart of monthly winter precipitation in North Carolina

3D pie-chart of monthly winter precipitation in North Carolina

Example 2

Bar-chart of different census map values:

d.vect.chart map=vectmap columns=cens51,cens61,cens71,cens81 chart_type=bar

Example 3

Creation of framed bar charts of an erodibiliy index from the Spearfish sample dataset:

g.region raster=erode.index -p
r.to.vect -s input=erode.index output=erode_index type=area 
v.extract input=erode_index output=erode_index_ctrds type=centroid 
d.rast aspect
d.vect.chart map=erode_index_ctrds chart_type=bar columns=cat \
             size=10 max_ref=12 scale=0.05 colors=yellow 
d.vect erode_index_ctrds icon=basic/circle fcol=black col=black size=5

Bar charts of an erodibiliy index (spatial subset)

AUTHOR

Radim Blazek, ITC-Irst, Trento, Italy

Last changed: $Date$