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)