NAME
    Geo::JSON - Perl OO interface for geojson

VERSION
    version 0.005

SYNOPSIS
        use Geo::JSON;
    
        my $obj = Geo::JSON->from_json( $json );
    
        $obj->to_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.

        The box is defined by a array of 2*n items, where n is the number of
        dimensions in a position. The items are the lowest value for an axis
        followed by the highest value for an axis, in the axis order used in
        the positions.

        The Co-ordinates Reference System for the bounding box is assumed to
        match that of the object.

    *   "crs"

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

GEOMETRY 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")

FEATURE OBJECTS
    *   Geo::JSON::Feature

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

FEATURE COLLECTION OBJECTS
    *   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.

  to_json
        $obj->to_json();
        $obj->to_json( $codec );

    Call on a Geo::JSON object. Returns the JSON that represents the object.

    Pass in an optional JSON codec to modify the default behaviour of the
    JSON returned.

  load
        my $obj = Geo::JSON->load( { type => 'Point', coordinates => ... } );

    Creates a Geo::JSON object from a hashref.

    This is used for coercion of attributes during object creation, and
    probably should not be called directly otherwise.

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.