Note: This document is for an older version of GRASS GIS that will be discontinued soon. You should upgrade, and read the current manual page.
NAME
v.reclass - Changes vector category values for an existing vector map according to results of SQL queries or a value in attribute table column.
KEYWORDS
vector,
reclassification,
attributes
SYNOPSIS
v.reclass
v.reclass --help
v.reclass input=name [layer=string] [type=string[,string,...]] output=name [column=name] [rules=name] [--overwrite] [--help] [--verbose] [--quiet] [--ui]
Flags:
- --overwrite
- Allow output files to overwrite existing files
- --help
- Print usage summary
- --verbose
- Verbose module output
- --quiet
- Quiet module output
- --ui
- Force launching GUI dialog
Parameters:
- input=name [required]
- Name of input vector map
- Or data source for direct OGR access
- layer=string
- Layer number or name
- Vector features can have category values in different layers. This number determines which layer to use. When used with direct OGR access this is the layer name.
- Default: 1
- type=string[,string,...]
- Input feature type
- Options: point, line, boundary, centroid
- Default: point,line,boundary,centroid
- output=name [required]
- Name for output vector map
- column=name
- The name of the column whose values are to be used as new categories
- The source for the new key column must be type integer or string
- rules=name
- Full path to the reclass rule file
v.reclass allows user to create a new vector map based on
the reclassification of an existing vector map. It also allows the user
to change the
key column away from the default of "
cat" with
the
column option.
Rules file may contain on each row either pair:
(separated by space) or comment beginning with '#' (hash).
Definition of new category begins with keyword
cat followed
by the new category value.
Keyword
where specifies SQL where condition.
No table is created for the reclassed map if the
column option is
used and the column type is integer (as the result could contain ambiguities).
If the
column option is used and the column type is string, a new
table is created containing the newly generated cat numbers and a single
column containing the unique string column values, sorted in alphabetical
order.
For dissolving common boundaries, see
v.dissolve.
Either the rules or column option must be specified.
v.reclass input=land output=land_u type=boundary rules=land.rcl
The rules file contains:
# land reclass file
cat 1
where use = 'E13' and owner = 'Jara Cimrman'
cat 2
where use = 'E14'
Produces a new vector area map
land_u containing boundaries from
land with area category values selected from database by SQL
select statement:
select id from tland where use = 'E13' and owner = 'Jara Cimrman'
changed to category 1;
values selected from database by SQL select statement:
select id from tland where use = 'E14' changed to category 2.
(North Carolina sample dataset)
v.reclass in=streams out=streams_by_type column=I_vs_P
v.db.select streams_by_type
cat|I_vs_P
1|intermittent
2|perennial
No table is created for reclassed layer if the
rules option is used.
v.dissolve,
v.extract
GRASS SQL interface
R.L. Glenn, USDA, SCS, NHQ-CGIS
from v.reclass to v.db.reclass and later to v.reclass in 5.7 rewritten
by Radim Blazek
SOURCE CODE
Available at:
v.reclass source code
(history)
Latest change: Wednesday Oct 04 13:48:26 2023 in commit: b3dbf4c0c04cce72d7615dc9531cf84bb8bb145b
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© 2003-2024
GRASS Development Team,
GRASS GIS 8.3.3dev Reference Manual