SHAPELIB(1)							   User Commands						       SHAPELIB(1)

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)

shapelib							   OCTOBER 2004 						       SHAPELIB(1)