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NAME

v.db.join - Joins a database table to a vector map table.

KEYWORDS

vector, database, attribute table

SYNOPSIS

v.db.join
v.db.join help
v.db.join map=name [layer=integer] column=string otable=string ocolumn=string [--verbose] [--quiet]

Parameters:

map=name
Vector map to which to join other table
layer=integer
Layer where to join
Default: 1
column=string
Join column in map table
otable=string
Other table name
ocolumn=string
Join column in other table

DESCRIPTION

v.db.join joins the content of another table into the connected attribute table of a vector map.

NOTES

v.db.join is a front-end to db.execute to allow easier usage. The vector attribute table must be stored in a SQL database (SQLite, PostgreSQL, MySQL, ODBC, ...). The DBF backend is not supported. Tables can be imported with db.in.ogr.

The vector map-database connection(s) can be verified with v.db.connect.

EXAMPLE

Joining the soil type explanations from table soils_legend into the Spearfish soils map (download legend):
g.copy vect=soils,mysoils

# import legend table
db.in.ogr soils_legend.csv out=soils_legend

# get join column names
v.info -c mysoils
db.describe -c soils_legend

# look at original table
v.db.select mysoils
cat|label
1|Aab
2|Ba
3|Bb
4|BcB
5|BcC
...

# look at legend
db.select soils_legend
db.select soils_legend | head -7
id|shortname|longname
0|no data|no data
0|AaB|Alice fine sandy loam, 0 to 6
0|Ba|Barnum silt loam
0|Bb|Barnum silt loam, channeled
0|BcB|Boneek silt loam, 2 to 6
0|BcC|Boneek silt loam, 6 to 9
...

# join soils_legend into mysoils attribute table
v.db.join mysoils col=label otable=soils_legend ocol=shortname

# verification of join
v.db.select mysoils
cat|label|id|shortname|longname
1|Aab|||
2|Ba|2|Ba|Barnum silt loam
3|Bb|3|Bb|Barnum silt loam, channeled
4|BcB|4|BcB|Boneek silt loam, 2 to 6
5|BcC|5|BcC|Boneek silt loam, 6 to 9
...

SEE ALSO

db.execute, db.in.ogr, v.db.update
GRASS SQL interface

AUTHOR

Markus Neteler

Last changed: $Date: 2011-11-08 01:42:51 -0800 (Tue, 08 Nov 2011) $


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