v.reclass(1grass) | Grass User's Manual | v.reclass(1grass) |
v.reclass - Changes vector category values for an existing vector map according to results of SQL queries or a value in attribute table column.
vector, reclassification, attributes
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]
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.
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.
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 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
Last changed: $Date: 2015-05-11 02:11:34 +0200 (Mon, 11 May 2015) $
Available at: v.reclass source code (history)
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