Geo::Shape(3pm) User Contributed Perl Documentation Geo::Shape(3pm)
NAME
Geo::Shape - base class for 2-dimensional points on the earth surface
INHERITANCE
Geo::Shape is extended by
Geo::Line
Geo::Point
Geo::Space
Geo::Surface
SYNOPSIS
use Geo::Shape;
my $p1 = Geo::Point->new(lat => 2.17, ...);
my $p2 = Geo::Point->latlong(2.17, 3.14); # wgs84 is default
my $p3 = $p1->in('wgs84'); # conversion
my $p4 = $p1->in('utm'); # conversion
DESCRIPTION
Base class for the many geo-spatial objects defined by the GeoPoint distribution.
METHODS
Constructors
Geo::Shape->new(OPTIONS)
Create a new object.
Option--Default
proj see Geo::Proj::defaultProjection()
. proj => LABEL
Attributes
$obj->proj
Returns the nickname of the projection used by the component. Be warned: this is not a Geo::Point object, but just a label.
$obj->proj4
Returns the proj4 object which handles the projection.
Projections
$obj->in(LABEL|'utm')
The coordinates of this point in a certain projection, refered to with the LABEL. The projection is defined with new(). When simply
'utm' is provided, the best UTM zone is selected.
In LIST context, the coordinates are returned. In SCALAR context, a new object is returned.
example:
my $gp = Geo::Point->latlong(1,2);
# implicit conversion to wgs84, if not already in latlong
my ($lat, $long) = $pr->latlong;
# will select an utm zone for you
my $p_utm = $gp->in('utm');
my ($x, $y) = $p_utm->xy;
my $label = $p_utm->proj;
my ($datum, $zone) = $label =~ m/^utm-(w+)-(d+)$/;
$obj->projectOn(NICK, POINTS)
The POINTS are ARRAYS with each an X and Y coordinate of a single point in space. A list of transformed POINTS is returned, which is
empty if no change is needed. The returned list is preceeded by a projection NICK which is the result, usually the same as the
provided NICK, but in some cases (for instance UTM) it may be different.
Geometry
$obj->area
Returns the area covered by the geo structure. Points will return zero.
$obj->bbox
Returns the bounding box of the object as four coordinates, respectively xmin, ymin, xmax, ymax. The values are expressed in the
coordinate system of the object.
$obj->bboxCenter
Returns a Geo::Point which represent the middle of the object. It is the center of the bounding box. The values is cached, once
computed.
Be warned that the central point in one projection system may be quite different from the central point in some other projectionsystem
.
$obj->bboxRing([XMIN, YMIN, XMAX, YMAX, [PROJ]])
Geo::Shape->bboxRing([XMIN, YMIN, XMAX, YMAX, [PROJ]])
Returns a Geo::Line which describes the outer bounds of the object called upon, counter-clockwise and left-bottom first. As class
method, you need to specify the limits and the PROJection.
$obj->distance(OBJECT, [UNIT])
Calculate the distance between this object and some other object. For many combinations of objects this is not supported or only
partially supported.
This calculation is performed with Geo::Distance in accurate mode. The default UNIT is kilometers. Other units are provided in the
manual page of Geo::Distance. As extra unit, "degrees" and "radians" are added as well as the "km" alias for kilometer.
$obj->perimeter
Returns the length of the outer border of the object's components. For points, this returns zero.
Display
$obj->deg2dm(DEGREES, POS, NEG)
Geo::Shape->deg2dm(DEGREES, POS, NEG)
Like deg2dms() but without showing seconds.
example:
print $point->deg2dm(0.12, 'e', 'w');
print Geo::Shape->deg2dm(0.12, 'e', 'w');
$obj->deg2dms(DEGREES, POS, NEG)
Geo::Shape->deg2dms(DEGREES, POS, NEG)
example:
print $point->deg2dms(0.12, 'e', 'w');
print Geo::Shape->deg2dms(0.12, 'e', 'w');
$obj->dms2deg(DMS)
Geo::Shape->dms2deg(DMS)
Accepts for instance 3d12'24.123, 3d12"E, 3.12314w, n2.14, s3d12", -12d34, and returns floating point degrees.
DIAGNOSTICS
Error: distance calculation not implemented between a $kind and a $kind
Only a subset of all objects can be used in the distance calculation. The limitation is purely caused by lack of time to implement
this.
Error: in() not implemented for a $class
SEE ALSO
This module is part of Geo-Point distribution version 0.93, built on May 19, 2010. Website: http://perl.overmeer.net/geo/ All modules in
this suite: "Geo::Point", "Geo::Proj4", "Geo::WKT", "Math::Polygon", "Geo::GML", "Geo::ISO19139", "Geo::EOP", "Geo::Format::Envisat", and
"Geo::Format::Landsat".
Please post questions or ideas to the mailinglist at http://geo-perl@list.hut.fi
LICENSE
Copyrights 2005-2010 by Mark Overmeer. For other contributors see ChangeLog.
This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself. See
http://www.perl.com/perl/misc/Artistic.html
perl v5.14.2 2010-05-19 Geo::Shape(3pm)