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

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.

       Either the rules or column option must be specified.

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

KNOWN ISSUES

       No table is created for reclassed layer if the rules option is used.

SEE ALSO

        v.dissolve, v.extract

       GRASS SQL interface

AUTHORS

       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)

       Accessed: Thursday Aug 01 11:31:16 2024

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       © 2003-2024 GRASS Development Team, GRASS GIS 8.4.0 Reference Manual