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 03:29:50 -0800 (Tue, 08 Nov 2011) $

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       © 2003-2013 GRASS Development Team