table of contents
Geo::Shape(3pm) | User Contributed Perl Documentation | Geo::Shape(3pm) |
NAME¶
Geo::Shape - base class for 2-dimensional points on the earth surfaceINHERITANCE¶
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.
. proj => LABEL
Option--Default proj see Geo::Proj::defaultProjection()
Attributes¶
$obj-> projReturns 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:
$obj-> projectOn(NICK, POINTS)
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) = $label =~ m/^utm-(\w+)-(\d+)$/;
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-> areaReturns 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:
$obj-> deg2dms(DEGREES, POS, NEG)
Geo::Shape-> deg2dms(DEGREES, POS, NEG)
print $point->deg2dm(0.12, 'e', 'w'); print Geo::Shape->deg2dm(0.12, 'e', 'w');
example:
$obj-> dms2deg(DMS)
Geo::Shape-> dms2deg(DMS)
print $point->deg2dms(0.12, 'e', 'w'); print Geo::Shape->deg2dms(0.12, 'e', 'w');
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 $kindOnly 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.fiLICENSE¶
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.html2010-05-19 | perl v5.14.2 |