package planar

import "github.com/paulmach/orb/planar"

Package planar computes properties on geometries assuming they are in 2d euclidean space.

Index ¶

• func Area(g orb.Geometry) float64
• func CentroidArea(g orb.Geometry) (orb.Point, float64)
• func Distance(p1, p2 orb.Point) float64
• func DistanceFrom(g orb.Geometry, p orb.Point) float64
• func DistanceFromSegment(a, b, point orb.Point) float64
• func DistanceFromSegmentSquared(a, b, point orb.Point) float64
• func DistanceFromWithIndex(g orb.Geometry, p orb.Point) (float64, int)
• func DistanceSquared(p1, p2 orb.Point) float64
• func Length(g orb.Geometry) float64
• func MultiPolygonContains(mp orb.MultiPolygon, point orb.Point) bool
• func PolygonContains(p orb.Polygon, point orb.Point) bool
• func RingContains(r orb.Ring, point orb.Point) bool

Examples ¶

• Area
• Distance
• Length

Functions ¶

func Area ¶

func Area(g orb.Geometry) float64

Area returns the area of the geometry in the 2d plane.

package main

import (
	"fmt"

	"github.com/paulmach/orb"
	"github.com/paulmach/orb/planar"
)

func main() {
	// +
	// |\
	// | \
	// |  \
	// +---+

	r := orb.Ring{{0, 0}, {3, 0}, {0, 4}, {0, 0}}
	a := planar.Area(r)

	fmt.Println(a)
}

6

func CentroidArea ¶

func CentroidArea(g orb.Geometry) (orb.Point, float64)

CentroidArea returns both the centroid and the area in the 2d plane. Since the area is need for the centroid, return both. Polygon area will always be >= zero. Ring area my be negative if it has a clockwise winding orider.

func Distance ¶

func Distance(p1, p2 orb.Point) float64

Distance returns the distance between two points in 2d euclidean geometry.

package main

import (
	"fmt"

	"github.com/paulmach/orb"
	"github.com/paulmach/orb/planar"
)

func main() {
	d := planar.Distance(orb.Point{0, 0}, orb.Point{3, 4})

	fmt.Println(d)
}

5

func DistanceFrom ¶

func DistanceFrom(g orb.Geometry, p orb.Point) float64

DistanceFrom returns the distance from the boundary of the geometry in the units of the geometry.

func DistanceFromSegment ¶

func DistanceFromSegment(a, b, point orb.Point) float64

DistanceFromSegment returns the point's distance from the segment [a, b].

func DistanceFromSegmentSquared ¶

func DistanceFromSegmentSquared(a, b, point orb.Point) float64

DistanceFromSegmentSquared returns point's squared distance from the segement [a, b].

func DistanceFromWithIndex ¶

func DistanceFromWithIndex(g orb.Geometry, p orb.Point) (float64, int)

DistanceFromWithIndex returns the minimum euclidean distance from the boundary of the geometry plus the index of the sub-geometry that was the match.

func DistanceSquared ¶

func DistanceSquared(p1, p2 orb.Point) float64

DistanceSquared returns the square of the distance between two points in 2d euclidean geometry.

func Length ¶

func Length(g orb.Geometry) float64

Length returns the length of the boundary of the geometry using 2d euclidean geometry.

package main

import (
	"fmt"

	"github.com/paulmach/orb"
	"github.com/paulmach/orb/planar"
)

func main() {
	// +
	// |\
	// | \
	// |  \
	// +---+

	r := orb.Ring{{0, 0}, {3, 0}, {0, 4}, {0, 0}}
	l := planar.Length(r)

	fmt.Println(l)
}

12

func MultiPolygonContains ¶

func MultiPolygonContains(mp orb.MultiPolygon, point orb.Point) bool

MultiPolygonContains checks if the point is within the multi-polygon. Points on the boundary are considered in.

func PolygonContains ¶

func PolygonContains(p orb.Polygon, point orb.Point) bool

PolygonContains checks if the point is within the polygon. Points on the boundary are considered in.

func RingContains ¶

func RingContains(r orb.Ring, point orb.Point) bool

RingContains returns true if the point is inside the ring. Points on the boundary are considered in.

Source Files ¶

area.go contains.go distance.go distance_from.go length.go