NAME

Geo::JSON - Perl OO interface for geojson

VERSION

version 0.004

SYNOPSIS

use Geo::JSON;

my $obj = Geo::JSON->from_json( $json );

DESCRIPTION

Convert to and from geojson using Perl objects. GeoJSON objects represent various geographical positions - points, lines, polygons, etc.

Currently in development - feedback welcome.

Currently supports 2 or 3 dimensions (longitude, latitude, altitude). Further dimensions in positions are ignored for calculations and comparisons, but will be read-from and written-to.

GEOJSON SPECIFICATION

See: http://www.geojson.org/geojson-spec.html

GEOJSON MEMBERS (ATTRIBUTES)

See the specification for the full details, but the basics are as follows:

• type

  Determines the object the json will be turned into

• position

  Not explicitly named in the json, but an array of at least two numbers representing a location in x, y, z order. (Either Easting, Northing, Altitude or Longitude, Latitude, Altitude as appropriate).

  Additional numbers may be present but ignored by this package for calculations.

• coordinates

  Defined in geometry objects (Point, MultiPoint, LineString, MultiLineString, Polygon, MultiPolygon). Will consist of a single position (Point), an array of positions (MultiPoint, LineString), an array of arrays of positions (MultiLineString, Polygon) or an array of arrays of arrays of positions (MultiPolygon). The positions within a single object should all have the same number of axes and be in the same axis order.

• bbox

  Optional, defining a bounding box that the position(s) are contained by. FIXME define bbox

• crs

  Optional, defining the Co-ordinates Reference System the object is using. See Geo::JSON::CRS for more details.

OBJECTS

• Geo::JSON::Point

  A single position

• Geo::JSON::MultiPoint

  An array of positions, representing multiple points

• Geo::JSON::LineString

  An array of 2 or more positions, represening a connected line

• Geo::JSON::MultiLineString

  An array of lines

• Geo::JSON::Polygon

  An array of lines, defining a polygon. The first line represents the outside of the polygon, subsequent lines define any 'holes'. The lines must be 'linear rings' - 4 or more points, with the first and last points being equivalent.

• Geo::JSON::MultiPolygon

  An array of polygons

• Geo::JSON::GeometryCollection

  An array of any of the above Geometry objects (as attribute geometries)

• Geo::JSON::Feature

  Any of the above objects (as attribute feature), together with a data structure (as attruibute properties)

• Geo::JSON::FeatureCollection

  An array of Feature objects (as attribute features)

METHODS

from_json

my $obj = Geo::JSON->from_json( $json );

Takes a geojson string, returns the object it represents.

CLASS METHODS

codec

Geo::JSON->codec->canonical(1)->pretty;

my $prev_codec = Geo::JSON->codec($new_codec);

Set options on or replace JSON codec.

THANKS

Tim Bunce - for codec suggestions and bug spotting.

SUPPORT

Bugs / Feature Requests

Please report any bugs or feature requests through the issue tracker at https://github.com/mjemmeson/geo-json/issues. You will be notified automatically of any progress on your issue.

Source Code

This is open source software. The code repository is available for public review and contribution under the terms of the license.

https://github.com/mjemmeson/geo-json

git clone git://github.com/mjemmeson/geo-json.git

AUTHOR

Michael Jemmeson <mjemmeson@cpan.org>

COPYRIGHT AND LICENSE

This software is copyright (c) 2013 by Michael Jemmeson <mjemmeson@cpan.org>.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.

cpanm Geo::JSON

perl -MCPAN -e shell
install Geo::JSON