## DESCRIPTION

v.to.db load values from vector map to database.

## NOTES

The units 'miles', 'feet', 'meters' and 'kilometers' are square for option=area.

When using option=coor on a vector area map, only coordinates of centroids with unique category will be reported.

## EXAMPLES

### Updating attribute tables

Note: Uploading of the attributes of a vector map to the DBMS has to be done column-wise. The column must be present in the table (use db.execute to add a new column if needed).

Upload category numbers to attribute table (used for new map):
`v.to.db map=soils type=area option=cat`

Upload area sizes of each polygon to attribute table:
`v.to.db map=soils type=area option=area col=area_size unit=h`

Upload line lengths (in meters) of each vector line to attribute table (use v.category in case of missing categories):
`v.to.db map=roads option=length type=line col=linelength units=me`

Upload x and y coordinates from vector geometry to attribute table:
`v.to.db map=pointsmap option=coor col=x,y`

Upload x, y and z coordinates from vector geometry to attribute table:
`v.to.db map=pointsmap option=coor col=x,y,z`

### Printing reports

Report all area sizes of a map:
`v.to.db -p soils option=area type=boundary units=h`

Report all area sizes of a map, sorted by category number:
`v.to.db -p soils option=area type=boundary units=h | sort -n`

Report all line lengths of a map:
`v.to.db -p roads option=length type=line units=k`

Report number of features for each category in map:
`v.to.db -p roads option=count type=line`

## NOTES

If the module is apparently slow and the map attributes are stored in an external DBMS such as PostgreSQL, it is highly recommended to create an index on the key (category) column.

## SEE ALSO

v.category

## AUTHOR

Radim Blazek

Last changed: $Date: 2005/05/10 09:04:44 $