NAME

       v.build  - Creates topology for vector map.
       Optionally also checks for topological errors.

KEYWORDS

       vector, topology, geometry

SYNOPSIS

       v.build
       v.build --help
       v.build  [-e]  map=name  [error=name]  option=string[,string,...]  [--overwrite]  [--help]
       [--verbose]  [--quiet]  [--ui]

   Flags:
       -e
           Extensive checks for topological errors
           Perform in-depth checks for topological errors when building topology

       --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:
       map=name [required]
           Name of vector map

       error=name
           Name for output vector map where erroneous vector features are written to

       option=string[,string,...] [required]
           Build topology or dump topology or indeces to standard output
           Options: build, dump, sdump, cdump, fdump
           Default: build
           build: build topology
           dump: write topology to stdout
           sdump: write spatial index to stdout
           cdump: write category index to stdout
           fdump: write feature index to stdout (OGR simple-feature-based formats only)

DESCRIPTION

       v.build builds support files for GRASS vector maps. These support  files  supply  topology
       and category information including spatial index that are needed by other GRASS modules.

       GRASS  is generating these support files automatically, only in rare cases the user has to
       (re)build them.

       Refer to vector data processing in GRASS GIS for more information  on  GRASS  vector  data
       model.

NOTES

       v.build  creates  support files only for vector maps located in the user’s current mapset.
       It’s not possible to rebuild support files  (option=build)  for  vector  maps  from  other
       mapsets.

       In  case  of  errors,  the user can optionally generate an error vector map containing the
       erroneous vectors for later inspection.

       If error vector map is specified, v.build checks:

           •   isolated bondaries (which are not forming any areas),

           •   centroids outside of area,

           •   duplicated centroids.

       Extensive checks for topological errors (flag -e) also includes:

           •   lines or boundaries of zero length,

           •   intersecting boundaries, ie. overlapping areas,

           •   areas without centroids that are not isles.

EXAMPLES

   Build topology
       Note that option=build recreates also spatial and category indeces, not only topology. For
       linked OGR layers (see v.external) also feature index is created.
       v.build map=urbanarea option=build
       Note that the vector map urbanarea must be located in the current mapset.

   Dump topology or indices
       Dump  options  print topology, spatial, category or feature index to standard output. Such
       information can be printed also for vector maps from other mapsets. A description  of  the
       vector  topology  is  available  in  the  GRASS GIS 7 Programmer’s Manual, section "Vector
       library topology management".
       v.build map=urbanarea option=dump

SEE ALSO

        v.build.all, v.build.polylines, v.edit, v.split

       See also wxGUI vector digitizer.

AUTHORS

       Dave Gerdes, U.S.Army Construction Engineering Research Laboratory,
       Michael Higgins, U.S.Army Construction Engineering Research Laboratory,
       Radim Blazek, ITC-irst, Trento, Italy

       Last changed: $Date: 2015-02-03 22:15:47 +0100 (Tue, 03 Feb 2015) $

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       © 2003-2016 GRASS Development Team, GRASS GIS 7.0.3 Reference Manual