func ToGjFeature(g *geos.Geometry) (gjFeature, error) { var gjf gjFeature gjf.Type = "Feature" gjf.Geometry.Type = "MultiPolygon" ngeoms, _ := g.NGeometry() gjf.Geometry.Coords = make([][][][]float64, ngeoms) for i := 0; i < ngeoms; i++ { subg, err := g.Geometry(i) if err != nil { return gjf, err } holes, err := subg.Holes() if err != nil { return gjf, err } gjf.Geometry.Coords[i] = make([][][]float64, 1+len(holes)) shell, err := subg.Shell() if err != nil { return gjf, err } coords, err := shell.Coords() if err != nil { return gjf, err } gjf.Geometry.Coords[i][0] = make([][]float64, len(coords)) for j, coord := range coords { gjf.Geometry.Coords[i][0][j] = make([]float64, 2) gjf.Geometry.Coords[i][0][j][0] = coord.X gjf.Geometry.Coords[i][0][j][1] = coord.Y } for k, hole := range holes { coords, err := hole.Coords() if err != nil { return gjf, err } gjf.Geometry.Coords[i][1+k] = make([][]float64, len(coords)) for j, coord := range coords { gjf.Geometry.Coords[i][1+k][j] = make([]float64, 2) gjf.Geometry.Coords[i][1+k][j][0] = coord.X gjf.Geometry.Coords[i][1+k][j][1] = coord.Y } } } return gjf, nil }
func drawPolygon(ctxt draw2d.GraphicContext, g *geos.Geometry, fillColor color.Color, strokeColor color.Color, width float64, scale func(x, y float64) (float64, float64)) { ctxt.SetFillColor(fillColor) ctxt.SetStrokeColor(strokeColor) ctxt.SetLineWidth(width) // exterior ring ring := geos.Must(g.ExteriorRing()) cs, err := ring.coordSeq() if err != nil { log.Fatal(err) } lineCoordSeq(ctxt, cs, scale) ctxt.FillStroke() // interior rings... }
func drawLine(ctxt draw2d.GraphicContext, g *geos.Geometry, c color.Color, width float64, scale func(x, y float64) (float64, float64)) { if c != nil { ctxt.SetStrokeColor(c) } if width != 0.0 { ctxt.SetLineWidth(width) } // XXX: should get a [] of points cs, err := g.coordSeq() if err != nil { log.Fatal(err) } lineCoordSeq(ctxt, cs, scale) ctxt.Stroke() }
//GetBoundingBox computes the bounding box for a given geometry func GetBoundingBox(g *geos.Geometry) (geographic.BoundingBox, error) { bbox := geographic.BoundingBox{} envelope, err := g.Envelope() if err != nil { return bbox, err } envelope, err = envelope.Shell() if err != nil { return bbox, err } centroid, err := envelope.Centroid() if err != nil { return bbox, err } bbox.LatitudeMinDeg, _ = centroid.Y() bbox.LongitudeMinDeg, _ = centroid.X() bbox.LatitudeMaxDeg = bbox.LatitudeMinDeg bbox.LongitudeMaxDeg = bbox.LongitudeMinDeg npoints, err := envelope.NPoint() if err != nil { return bbox, err } for i := 0; i < npoints; i++ { pt := geos.Must(envelope.Point(i)) lon, _ := pt.X() lat, _ := pt.Y() if lon < bbox.LongitudeMinDeg { bbox.LongitudeMinDeg = lon } if lon > bbox.LongitudeMaxDeg { bbox.LongitudeMaxDeg = lon } if lat < bbox.LatitudeMinDeg { bbox.LatitudeMinDeg = lat } if lat > bbox.LatitudeMaxDeg { bbox.LatitudeMaxDeg = lat } } return bbox, nil }
//IntersectsFilter creates a Filter allowing to skip tiles outside of a given geometry func IntersectsFilter(g *geos.Geometry) raster.Filter { //TODO: use a prepared geometry return func(level, x, y int) (bool, error) { tile, err := newTilePolygon(level, x, y) if err != nil { return false, err } intersects, err := g.Intersects(tile) if err != nil { return false, err } return !intersects, nil //Tiles that do not intersect are excluded } }
func drawPoint(ctxt draw2d.GraphicContext, g *geos.Geometry, c color.Color, radius float64, scale func(x, y float64) (float64, float64)) { if c != nil { ctxt.SetFillColor(c) } x, err := g.X() if err != nil { log.Fatal(err) } y, err := g.Y() if err != nil { log.Fatal(err) } x, y = scale(x, y) ctxt.MoveTo(x, y) ctxt.ArcTo(x, y, radius, radius, 0, 2*math.Pi) ctxt.Fill() }
func envelope(g *geos.Geometry) Envelope { env, err := g.Envelope() if err != nil { log.Fatal(err) } ring, err := env.ExteriorRing() if err != nil { log.Fatal(err) } cs, err := ring.coordSeq() if err != nil { log.Fatal(err) } getX := getOrd(cs, (*geos.CoordSeq).GetX) getY := getOrd(cs, (*geos.CoordSeq).GetY) return Env(getX(0), getY(0), getX(2), getY(2)) }
// Returns the bounding box of the geos.Geometry as a rtreego.Rect func RtreeBboxg(g *geos.Geometry, tol float64) (*rtreego.Rect, error) { env, err := g.Envelope() if err != nil { return nil, err } shell, _ := env.Shell() if err != nil { return nil, err } c, err := shell.Coords() if err != nil { return nil, err } return rtreego.NewRect(rtreego.Point{c[0].X, c[0].Y}, []float64{math.Max(tol, c[2].X-c[0].X), math.Max(tol, c[2].Y-c[0].Y)}) }