NAME
v.db.join - Joins a database table to a vector map table.
KEYWORDS
vector,
attribute table,
database
SYNOPSIS
v.db.join
v.db.join --help
v.db.join map=name [layer=string] column=name other_table=name other_column=name [subset_columns=name[,name,...]] [--help] [--verbose] [--quiet] [--ui]
Flags:
- --help
- Print usage summary
- --verbose
- Verbose module output
- --quiet
- Quiet module output
- --ui
- Force launching GUI dialog
Parameters:
- map=name [required]
- Name of vector map
- Vector map to which to join other table
- layer=string
- Layer number or name
- Layer where to join
- Default: 1
- column=name [required]
- Identifier column (e.g.: cat) in the vector table to be used for join
- other_table=name [required]
- Other table name
- other_column=name [required]
- Identifier column (e.g.: id) in the other table used for join
- subset_columns=name[,name,...]
- Subset of columns from the other table
v.db.join joins the content of another table into the connected
attribute table of a vector map.
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.
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 other_table=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
...
db.execute,
db.in.ogr,
v.db.update
GRASS SQL interface
Markus Neteler
Last changed: $Date: 2014-11-28 17:25:40 +0100 (Fri, 28 Nov 2014) $
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