NAME

       shprewind - fix polygon ring orientations in ESRI shapefiles

SYNOPSIS

       shprewind infile outfile

DESCRIPTION

       Makes a copy of the shapefile infile to outfile 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 infile and
       attempting  to  open  the files infile.shp or infile.SHP, and infile.shx or infile.SHX for
       the respective data and index files.  The files to create from outfile are  determined  by
       stripping any filename extension from outfile and appending .shp and .shx suffixes for the
       respective data and index files.

EXIT STATUS

       0      Successful program execution.

       1      Missing infile or outfile arguments, failed to  open  shapefile  infile  or  create
              shapefile outfile.

DIAGNOSTICS

       The following diagnostics may be issued on stdout:

       Unable to open:infile

       Unable to create:outfile

       count objects rewound.

AUTHORS

       Frank Warmerdam (warmerdam@pobox.com) is the maintainer of the shapelib shapefile library.
       Joonas Pihlaja (jpihlaja@cc.helsinki.fi) wrote this man page.

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), dbfcreate(1), dbfdump(1), dbf_dump(1), shpadd(1), shpcreate(1), shpdump(1)