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, reclass, attributes
SYNOPSIS¶
v.reclass
v.reclass help
v.reclass input=
name output=
name
[
type=
string[,
string,...]] [
layer=
integer]
[
column=
name] [
rules=
name] [--
overwrite]
[--
verbose] [--
quiet]
Flags:¶
- --overwrite
-
Allow output files to overwrite existing files
- --verbose
-
Verbose module output
- --quiet
-
Quiet module output
Parameters:¶
- input=name
-
Name of input vector map
- output=name
-
Name for output vector map
- type=string[,string,...]
-
Feature type
Options: point,line,boundary,centroid
Default: point,line,boundary,centroid
- layer=integer
-
Layer number
A single vector map can be connected to multiple database tables. This
number determines which table to use.
Default: 1
- 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
DESCRIPTION¶
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:
keyword value
(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.
NOTES¶
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.
EXAMPLES¶
Example 1: Reclass by rules¶
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.
Example 2: Reclass by attribute column¶
(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
BUGS¶
No table is created for reclassed layer if
rules option is used.
SEE ALSO¶
v.dissolve, v.extract
GRASS SQL interface
AUTHOR¶
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
Last changed: $Date: 2011-11-08 12:29:50 +0100 (Tue, 08 Nov 2011) $
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