1SHPREWIND(1)                       shapelib                       SHPREWIND(1)
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NAME

6       shprewind - validates and resets the winding order of rings
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SYNOPSIS

9       shprewind in_shp_file out_shp_file
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DESCRIPTION

12       Validates  and  resets the winding order of rings in polygon geometries
13       to match the ordering required by shapefile specification. This is use‐
14       ful  for shapefiles having troubles when checked with a ´shpdump -vali‐
15       date´.
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17       Makes a copy of the shapefile in_shp_file to out_shp_file and fixes the
18       orientation  of  points in the rings of Polygon, PolygonZ, and PolygonM
19       typed shapes to conform to the shapefile  specification.  According  to
20       the  specification,  the  vertices  of  outer  rings should be oriented
21       clockwise on the X/Y plane, and those of inner rings counterclockwise.
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23       Shapefiles actually consist of two files with the same basename and ex‐
24       tensions .shp and .shx (or .SHP and .SHX) containing the shape data and
25       shape index respectively. The files to open  are  determined  by  first
26       stripping  any  filename  extension  from in_shp_file and attempting to
27       open the files in_shp_file.shp or in_shp_file.SHP, and  in_shp_file.shx
28       or  in_shp_file.SHX  for the respective data and index files. The files
29       to create from out_shp_file are determined by  stripping  any  filename
30       extension  from  out_shp_file  and appending .shp and .shx suffixes for
31       the respective data and index files.
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OPTIONS

34       in_shp_file
35              the name of an existing shapefile.
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37       out_shp_file
38              the name of the new fixed shapefile that will be created.
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EXIT STATUS

41       0      Successful program execution.
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43       1      Missing in_shp_file or out_shp_file arguments,  failed  to  open
44              shapefile in_shp_file or create shapefile out_shp_file.
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DIAGNOSTICS

47       The following diagnostics may be issued on stdout:
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49       Unable to open:in_shp_file
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51       Unable to create:out_shp_file
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53       count objects rewound.
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EXAMPLE

56       shprewind badshapefile newshapefile
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AUTHOR

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

65       The implementation assumes that there is at most one outer ring in each
66       shape,  that  it is the first ring in a shape, and all other rings in a
67       shape are inner rings. Polygons inside MultiPatch  shape  types  aren´t
68       rewound.
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SEE ALSO

71       dbfadd(1),  dbfcat(1), dbfcreate(1), dbfdump(1), dbfinfo(1), shpadd(1),
72       shpcat(1),  shpcentrd(1),  shpcreate(1),  shpdump(1),  shpdxf(1),  shp‐
73       fix(1), shpinfo(1), shpproj(1), shptest(1)
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77                                  March 2022                      SHPREWIND(1)
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