104 lines
2.3 KiB
Go
104 lines
2.3 KiB
Go
package geos
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/*
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#cgo LDFLAGS: -lgeos_c
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#include "geos_c.h"
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#include <stdlib.h>
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*/
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import "C"
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func (this *Geos) Contains(a, b *Geom) bool {
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result := C.GEOSContains_r(this.v, a.v, b.v)
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if result == 1 {
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return true
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}
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// result == 2 -> exception (already logged to console)
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return false
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}
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func (this *Geos) Intersects(a, b *Geom) bool {
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result := C.GEOSIntersects_r(this.v, a.v, b.v)
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if result == 1 {
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return true
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}
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// result == 2 -> exception (already logged to console)
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return false
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}
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func (this *Geos) Intersection(a, b *Geom) *Geom {
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result := C.GEOSIntersection_r(this.v, a.v, b.v)
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if result == nil {
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return nil
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}
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geom := &Geom{result}
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return geom
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}
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func (this *Geos) Buffer(geom *Geom, size float64) *Geom {
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buffered := C.GEOSBuffer_r(this.v, geom.v, C.double(size), 50)
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if buffered == nil {
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return nil
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}
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return &Geom{buffered}
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}
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func (this *Geos) SimplifyPreserveTopology(geom *Geom, tolerance float64) *Geom {
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simplified := C.GEOSTopologyPreserveSimplify_r(this.v, geom.v, C.double(tolerance))
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if simplified == nil {
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return nil
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}
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return &Geom{simplified}
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}
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// UnionPolygons tries to merge polygons.
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// Returns a single (Multi)Polygon.
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// Destroys polygons and returns new allocated (Multi)Polygon as necessary.
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func (this *Geos) UnionPolygons(polygons []*Geom) *Geom {
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if len(polygons) == 0 {
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return nil
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}
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if len(polygons) == 1 {
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return polygons[0]
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}
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multiPolygon := this.MultiPolygon(polygons)
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if multiPolygon == nil {
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return nil
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}
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defer this.Destroy(multiPolygon)
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result := C.GEOSUnaryUnion_r(this.v, multiPolygon.v)
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if result == nil {
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return nil
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}
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return &Geom{result}
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}
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// LineMerge tries to merge lines. Returns slice of LineStrings.
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// Destroys lines and returns new allocated LineString Geoms.
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func (this *Geos) LineMerge(lines []*Geom) []*Geom {
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if len(lines) <= 1 {
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return lines
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}
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multiLineString := this.MultiLineString(lines)
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if multiLineString == nil {
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return nil
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}
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defer this.Destroy(multiLineString)
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merged := C.GEOSLineMerge_r(this.v, multiLineString.v)
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if merged == nil {
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return nil
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}
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geom := &Geom{merged}
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if this.Type(geom) == "LineString" {
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return []*Geom{geom}
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}
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// extract MultiLineString
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lines = make([]*Geom, 0, this.NumGeoms(geom))
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for _, line := range this.Geoms(geom) {
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lines = append(lines, this.Clone(line))
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}
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this.Destroy(geom)
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return lines
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}
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