NAME
d.rast.pg - Generate or display a reclass map based on the
unique values in a database column. (GRASS-RDBMS Interface Display Program)
SYNOPSIS
d.rast.pg
d.rast.pg help
d.rast.pg key=name tab=name col=name [lab=name]
[where=name] input=name [output=name]
ALTERNATE
d.rast.pg -s help
d.rast.pg -s sql=filename input=name [output=name]
DESCRIPTION
d.rast.pg displays a raster image in which each category represents
a unique value in a database column. Values are retrieved from the current
database based on a user defined SQL SELECT statement. The current database
is identified by the GRASS environment variable $PG_DBASE which is set
using the g.select.pg GRASS-RDBMS interface tool. The output from
this program is a set of GRASS reclass rules which are used to create or
display a reclassed raster surface based on the attributes returned from
the database and the raster data layer specified as the input map.
COMMAND LINE OPTIONS
Parameters:
-
key=databasecolumnname
-
Column corresponding to category values in raster map [input]
-
tab=databasetablename
-
Table containing [col]
-
col=databasecolumnname
-
Column to base reclass on
where=clause
-
Where clause for query (ie. where col='paved')
lab=name
-
Column to use as labels (optional)
-
input=map
-
Name of existing raster file
-
output=map
-
Name of new reclass map
ALTERNATE COMMAND LINE USAGE
The alternate command line structure is selected using the the [-s]
flag on the command line. When using this flag the user must include the
name of a text file on the command line as well. This file must include
a complete, well formed SQL SELECT statement.
Flag:
-
-s
-
SQL statement is input from a prepared file
Parameters:
-
sql=filename
-
SQL statement specifying well formed selection criteria.
-
input=map
-
Name of an existing raster map
-
output=map
-
Name of a new reclass file
EXAMPLE 1:
d.rast.pg input=kur_rast_id output=soils2 tab=info_kuruma key=rec_id
col=soils_id lab=soils_info.name where="soils_info.type_id = soils_id"
RESULT:
This example will create a raster map soils2 with a category
for each unique value taken from the field "soils_id" from table info_kuruma,
with label of value of the column "name" from the table soils_info.
The raster map will be a reclassed data layer based on the input raster
map kur_rast_id.
EXAMPLE 2:
d.rast.pg -s sql=raster.sql input=kur_rast_id output=soils3
raster.sql:
select rec_id, soils_info.type_id from info_kuruma where soils_info.name
~ 'barren' and soils_info.type_id = soils_id
RESULT:
This example will create a raster map soils3 with a category
for each unique value taken from the column "type_id" from the table soils_info,
with only 'barren' type. The raster map will be a reclassed
data layer based on the input raster map kur_rast_id. Note that
there must be two fields in the SELECT statement (these for the old and
new values).
In this example, the input map kur_rast_id was prepared by v.to.rast
from the vector are map kuruma_id, which is approximately 7,000
polygons with unique ids (corresponding to rec_id field in the table
info_kuruma).
BUGS
None known.
NOTE
This program requires the Postgres database software. It uses the GRASS
module r.reclass started from inside it.
SEE ALSO
g.column.pg, g.select.pg,
g.stats.pg,
g.table.pg,
d.site.pg,
d.vect.pg,
d.what.r.pg,
d.what.s.pg,
d.what.v.pg,
r.reclass.pg,
r.rescale.pg,
v.reclass.pg
AUTHOR
Original Informix SQL-tools: James A. Farley, Wang Song, and W. Fredrick
Limp University of Arkansas, CAST
Postgres modifications: Janne Soimasuo, Faculty of Forestry, University
of Joensuu, Finland.
Updated to GRASS 5 by Alex Shevlakov (sixote@yahoo.com)