## DESCRIPTION

v.what.rast3 reads 3D raster value for each point in the vector and updates col column in vector attribute table by this value. The column should be type double. This module is based on v.what.rast.
If more points have the same category, attribute value is set to NULL. If 3D raster values is NULL, attribute value is set to NULL.

## NOTES

## EXAMPLES

A) Reading values from 3D raster map at position of vector points, writing these values into a column of the attribute table connected to the vector map:

    v.what.rast3 map=pnts raster3d=plume column=concentration

B) In case of a vector map without attached attribute table, first add a new attribute table. This table is then populated with values queried from the raster map:

    # create new random 3d vector points map
    v.random -z output=pnts npoints=100 zmin=0  zmax=50

    # add new table, link to map
    v.db.addtable map=pnts column="concentration double precision"

    # query raster map and upload values to vector table into specified column
    g.region raster3d=plume -p
    v.what.rast3 map=pnts raster3d=plume column=concentration

    # verify new attribute table:
    v.db.select map=pnts

    # verify statistics of uploaded values:
    v.univar map=pnts column=concentration type=point

## SEE ALSO

v.db.addtable, v.db.select, v.what.rast, v.what.vect, v.univar

## AUTHOR

Soeren Gebbert, heavily based on v.what.rast by Radim Blazek

Last changed: $Date$