v.reclass - Changes vector category values for an existing vector map according to results of SQL

       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

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 keycolumn 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.

Example1:Reclassbyrules
       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.

   Example2:Reclassbyattributecolumn
       (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

       vector, reclassification, attributes

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

v.reclass   -  Changes  vector  category  values  for  an existing vector map according to results of SQL
       queries or a value in attribute table column.

       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.dissolve,v.extractGRASSSQLinterface

       Available at: v.reclass source code (history)

       Accessed: Friday Apr 04 01:20:32 2025

       Main index | Vector index | Topics index | Keywords index | Graphical index | Full index

       © 2003-2025 GRASS Development Team, GRASS GIS 8.4.1 Reference Manual

GRASS 8.4.1                                                                                    v.reclass(1grass)

v.reclassv.reclass--helpv.reclassinput=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: 1type=string[,string,...]
           Input feature type
           Options: point,line,boundary,centroid
           Default: point,line,boundary,centroidoutput=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