shprewind - Online in the Cloud

PROGRAM:

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

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