The program will query the contents of the vector map layer named by the user on the command line. This map layer must exist in the user's current mapset search path.
The program activates the mouse, and expects the user to indicate the location(s) to be queried by depressing a mouse button over desired location(s) within the current geographic region in the active display frame on the graphic monitor.
The query may be repeated as often as desired using the left mouse button. The right button on the mouse is used to quit the d.what.vect session.
Users can also use this program inside of shell scripts that require as input a map category value and a mouse button depressed. Users can set the -1 flag to run d.what.vect only once, and return only the map category value found and the number of the mouse button depressed. (Mouse button return values are as follows: 0 indicates no button was pressed, 1 indicates that the left mouse button was pressed, 2 indicates the middle button was pressed, and 3 indicates that the right mouse button was pressed.)
d.what.vect will always print its output to the user's terminal screen. d.what.vect output can be redirected into a file; however, if it is, the output will go both to the screen and to the file. For example:
d.what.rast can be used to interactively query the map category contents of multiple raster map layers at user-selected locations.