Geo::Line(3pm)

User Contributed Perl Documentation

Geo::Line(3pm)

NAME¶

Geo::Line - a sequence of connected points

INHERITANCE¶

 Geo::Line
   is a Geo::Shape
 Geo::Line
   is a Math::Polygon

SYNOPSIS¶

 my $line  = Geo::Line->new(points => [$p1, $p2]);
 my $line  = Geo::Line->line($p1, $p2);
 my $ring  = Geo::Line->ring($p1, $p2, $p3, $p1);
 my $ring  = Geo::Line->ring($p1, $p2, $p3);
 my $plane = Geo::Line->filled($p1, $p2, $p3, $p1);
 my $plane = Geo::Line->filled($p1, $p2, $p3);

DESCRIPTION¶

A 2-dimensional sequence of connected points. The points will be forced to use the same projection.

METHODS¶

Constructors¶

Geo::Line-> bboxFromString(STRING, {PROJECTION])

Create a square from the STRING. The coordinates can be separated by a comma (preferrably), or blanks. When the coordinates end on NSEW, the order does not matter, otherwise lat-long or xy order is presumed.

This routine is very smart. It understands
PROJLABEL: <4 coordinates in any order, but with NSEW>
...

example: bbox from string

 my $x = '5n 2n 3e e12';       # coordinates in any order
 my $x = '5e , 2n, 3n, e12';    # coordinates in any order
 my $x = '2.12-23.1E, N1-4';   # stretches
 my $x = 'wgs84: 2-5e, 1-8n';  # starts with projection
 my $x = 'wgs84: e2d12' -3d, n1, n7d12'34"';
 my ($xmin, $ymin, $xmax, $ymax, $proj)
    = Geo::Line->bboxFromString($x);
 my $p = Geo::Line->ringFromString($x);
 # When parsing user applications, you probably want:
 my $p = eval { Geo::Line->bboxFromString($x) };
 warn $@ if $@;

$obj-> filled(POINTS, OPTIONS)

Geo::Line-> filled(POINTS, OPTIONS)

The POINTS form a ring() and the filled is part of the geometrical shape.

$obj-> line(POINTS, OPTIONS)

Geo::Line-> line(POINTS, OPTIONS)

construct a line, which will probably not have the same begin and end point. The POINTS are passed as new(points), and the other OPTIONS are passed to new() as well.

$obj-> new([OPTIONS], [POINTS], [OPTIONS])

Geo::Line-> new([OPTIONS], [POINTS], [OPTIONS])

When called as instance method, the projection, ring, and filled attributes are taken from the initiator, like a clone with modification.

 Option   --Defined in     --Default
 bbox       Math::Polygon    undef
 clockwise  Math::Polygon    undef
 filled                      <false>
 points                      <data>
 proj       Geo::Shape       see Geo::Proj::defaultProjection()
 ring                        <false>

. bbox => ARRAY

. clockwise => BOOLEAN

. filled => BOOLEAN

Implies ring. The filled of the ring is included in the geometrical shape.

. points => ARRAY-OF-POINTS|ARRAY-OF-COORDINATES

With this option, you can specify either Geo::Point objects, or coordinate pairs which will get transformed into such objects. WARNING: in that case, the coordinates must be in xy order.

. proj => LABEL

. ring => BOOLEAN

The first point is the last point. When specified, you have to make sure that this is the case. If ring() is used to create this object, that routine will check/repair it for you.

example:

 my $point = Geo::Point->xy(1, 2);
 my $line  = Geo::Line->new
   ( points => [$point, [3,4], [5,6], $point]
   , ring   => 1
   )'

$obj-> ring(POINTS, OPTIONS)

Geo::Line-> ring(POINTS, OPTIONS)

The first and last point will be made the same: if not yet, than a reference to the first point is appended to the list. A "ring" does not cover the internal.

Geo::Line-> ringFromString(STRING, [PROJECTION])

Calls bboxFromString() and then produces a ring object from than. Don't forget the "eval" when you call this method.

Attributes¶

$obj-> geopoint(INDEX, [INDEX, ..])

Returns the Geo::Point for the point with the specified INDEX or indices.

$obj-> geopoints

In LIST context, this returns all points as separate scalars: each is a Geo::Point with projection information. In SCALAR context, a reference to the coordinates is returned.

With points(), you get arrays with XY coordinates returned, but without the projection information. That will be much faster, but not sufficient for some uses.

$obj-> isFilled

Returns a true value is the internals of the ring of points are declared to belong to the shape.

$obj-> isRing

Returns a true value if the sequence of points are a ring or filled: the first point is the last.

$obj-> nrPoints

See "Attributes" in Math::Polygon

$obj-> order

See "Attributes" in Math::Polygon

$obj-> point(INDEX, [INDEX, ...])

See "Attributes" in Math::Polygon

$obj-> points

See "Attributes" in Math::Polygon

$obj-> proj

See "Attributes" in Geo::Shape

$obj-> proj4

See "Attributes" in Geo::Shape

Projections¶

$obj-> in(LABEL|'utm')

See "Projections" in Geo::Shape

$obj-> projectOn(NICK, POINTS)

See "Projections" in Geo::Shape

Geometry¶

$obj-> area

Returns the area enclosed by the polygon. Only useful when the points are in some orthogonal projection.

$obj-> bbox

The bounding box coordinates. These are more useful for rings than for open line pieces.

$obj-> bboxCenter

See "Geometry" in Geo::Shape

$obj-> bboxRing([XMIN, YMIN, XMAX, YMAX, [PROJ]])

Geo::Line-> bboxRing([XMIN, YMIN, XMAX, YMAX, [PROJ]])

See "Geometry" in Geo::Shape

$obj-> beautify(OPTIONS)