NAME

v.to.db - Load values from vector to database. In uploaded/printed category values '-1' is used for 'no category' and 'null'/'-' if category cannot be found or multiple categories were found.

SYNOPSIS

v.to.db
v.to.db help
v.to.db [-ps] map=string [type=string[,string,...]] [field=integer] [qfield=integer] option=string [units=string] [col=string[,string,...]] [qcol=string]

Flags:

-p
print only
-s
print only sql statements

Parameters:

map=string
Name of input vector
type=string
Type of elements (for coor valid point/centroid, for length valid line/boundary)
Options: point,line,boundary,centroid
Default: point,line,boundary,centroid
field=integer
Field value
Default: 1
qfield=integer
Query field. Used by 'query' option.
Default: 1
option=string
Uploaded value:
cat - insert new row for each category if doesn't exist yet
area - area size
length - line length
count - number of features for each category
coor - point coordinates, X,Y or X,Y,Z
sides - categories of areas on the left and right side of the boundary,
'qfield' is used for area category.
query - result of a database query for all records of the geometry
(or geometries) from table specified by 'qfield' option
Options: cat,area,length,count,coor,sides,query
units=string
mi(les),f(eet),me(ters),k(ilometers),a(cres),h(ectares)
Options: mi,miles,f,feet,me,meters,k,kilometers,a,acres,h,hectares
col=string
column(s)
qcol=string
Query column used for 'query' option. E.g. 'cat', 'count(*)', 'sum(val)'

DESCRIPTION

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

NOTES

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

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 featurs 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: 2004/11/05 15:21:12 $


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