90 lines
1.8 KiB
Go
90 lines
1.8 KiB
Go
package geom
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import (
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"goposm/element"
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"goposm/geom/geos"
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)
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type GeomError struct {
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message string
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level int
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}
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func (e *GeomError) Error() string {
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return e.message
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}
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func (e *GeomError) Level() int {
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return e.level
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}
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func NewGeomError(message string, level int) *GeomError {
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return &GeomError{message, level}
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}
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var (
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ErrorOneNodeWay = NewGeomError("need at least two separate nodes for way", 0)
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)
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func PointWKB(g *geos.GEOS, node element.Node) ([]byte, error) {
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coordSeq, err := g.CreateCoordSeq(1, 2)
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if err != nil {
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return nil, err
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}
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// coordSeq inherited by LineString
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coordSeq.SetXY(g, 0, node.Long, node.Lat)
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geom, err := coordSeq.AsPoint(g)
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if err != nil {
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return nil, err
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}
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defer g.Destroy(geom)
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return g.AsWKB(geom)
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}
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func LineStringWKB(g *geos.GEOS, nodes []element.Node) ([]byte, error) {
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if len(nodes) < 2 {
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return nil, ErrorOneNodeWay
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}
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coordSeq, err := g.CreateCoordSeq(uint32(len(nodes)), 2)
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if err != nil {
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return nil, err
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}
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// coordSeq inherited by LineString
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for i, nd := range nodes {
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coordSeq.SetXY(g, uint32(i), nd.Long, nd.Lat)
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}
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geom, err := coordSeq.AsLineString(g)
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if err != nil {
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return nil, err
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}
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defer g.Destroy(geom)
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return g.AsWKB(geom)
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}
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func PolygonWKB(g *geos.GEOS, nodes []element.Node) ([]byte, error) {
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coordSeq, err := g.CreateCoordSeq(uint32(len(nodes)), 2)
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if err != nil {
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return nil, err
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}
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// coordSeq inherited by LineString, no destroy
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for i, nd := range nodes {
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err := coordSeq.SetXY(g, uint32(i), nd.Long, nd.Lat)
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if err != nil {
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return nil, err
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}
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}
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geom, err := coordSeq.AsLinearRing(g)
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if err != nil {
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return nil, err
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}
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// geom inherited by Polygon, no destroy
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geom = g.CreatePolygon(geom, nil)
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if err != nil {
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return nil, err
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}
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defer g.Destroy(geom)
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return g.AsWKB(geom)
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}
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