NAME

       shprewind - validates and resets the winding order of rings

       ##SYNOPSIS shprewind in_shp_file out_shp_file

       ##DESCRIPTION Validates and resets the winding order of rings in polygon geometries to match the ordering
       required  by  shapefile  specification. This is useful for shapefiles having troubles when checked with a
       'shpdump -validate'.

       Makes a copy of the shapefile in_shp_file to out_shp_file and fixes the  orientation  of  points  in  the
       rings  of  Polygon,  PolygonZ,  and  PolygonM  typed  shapes  to  conform to the shapefile specification.
       According to the specification, the vertices of outer rings should  be  oriented  clockwise  on  the  X/Y
       plane, and those of inner rings counterclockwise.

       Shapefiles actually consist of two files with the same basename and extensions .shp and .shx (or .SHP and
       .SHX)  containing  the shape data and shape index respectively. The files to open are determined by first
       stripping any filename extension from in_shp_file and attempting to open  the  files  in_shp_file.shp  or
       in_shp_file.SHP,  and  in_shp_file.shx  or  in_shp_file.SHX  for the respective data and index files. The
       files to create from out_shp_file are determined by stripping any filename  extension  from  out_shp_file
       and appending .shp and .shx suffixes for the respective data and index files.

       ##OPTIONS

       in_shp_file
              the name of an existing shapefile.

       out_shp_file
              the name of the new fixed shapefile that will be created.

       ##EXIT STATUS

       0      Successful program execution.

       1      Missing  in_shp_file  or  out_shp_file  arguments,  failed to open shapefile in_shp_file or create
              shapefile out_shp_file.

       ##DIAGNOSTICS The following diagnostics may be issued on stdout:

       Unable to open:in_shp_file

       Unable to create:out_shp_file

       count objects rewound.

       ##EXAMPLE shprewind badshapefile newshapefile

       ##AUTHOR shprewind is part of shapelib, maintained by Frank Warmerdam. This guide was created by  Eduardo
       Patoo  Kanegae  and  converted to manpage by Johan Van de Wauw. It was further enhanced with the man page
       written by Joonas Pihlaja (jpihlaja@cc.helsinki.fi).

       ##BUGS The implementation assumes that there is at most one outer ring in each  shape,  that  it  is  the
       first  ring  in a shape, and all other rings in a shape are inner rings. Polygons inside MultiPatch shape
       types aren't rewound.

       ##SEE  ALSO  dbfadd(1),  dbfcat(1),   dbfcreate(1),   dbfdump(1),   dbfinfo(1),   shpadd(1),   shpcat(1),
       shpcentrd(1), shpcreate(1), shpdump(1), shpdxf(1), shpfix(1), shpinfo(1), shpproj(1), shptest(1)

                                                   August 2024                                      SHPREWIND(1)