Polygon index (#406)

* Polygon index

* Polyline files

go.mod

@@ -26,6 +26,7 @@ require (
 	github.com/spf13/cobra v1.8.1
 	github.com/spf13/pflag v1.0.5
 	github.com/stretchr/testify v1.9.0
+	github.com/tidwall/rtree v1.10.0
 	github.com/twpayne/go-geom v1.4.1
 	github.com/twpayne/go-polyline v1.1.1
 	google.golang.org/protobuf v1.33.0
@@ -65,10 +66,11 @@ require (
 	github.com/pkg/browser v0.0.0-20240102092130-5ac0b6a4141c // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
 	github.com/russross/blackfriday/v2 v2.1.0 // indirect
-	golang.org/x/crypto v0.31.0 // indirect
-	golang.org/x/net v0.33.0 // indirect
-	golang.org/x/sync v0.10.0 // indirect
+	github.com/tidwall/geoindex v1.7.0 // indirect
+	golang.org/x/crypto v0.24.0 // indirect
+	golang.org/x/net v0.26.0 // indirect
+	golang.org/x/sync v0.7.0 // indirect
 	golang.org/x/sys v0.30.0 // indirect
-	golang.org/x/text v0.21.0 // indirect
+	golang.org/x/text v0.16.0 // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect
 )

go.sum

@@ -178,6 +178,14 @@ github.com/stretchr/testify v1.6.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/
 github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
 github.com/stretchr/testify v1.9.0 h1:HtqpIVDClZ4nwg75+f6Lvsy/wHu+3BoSGCbBAcpTsTg=
 github.com/stretchr/testify v1.9.0/go.mod h1:r2ic/lqez/lEtzL7wO/rwa5dbSLXVDPFyf8C91i36aY=
+github.com/tidwall/cities v0.1.0 h1:CVNkmMf7NEC9Bvokf5GoSsArHCKRMTgLuubRTHnH0mE=
+github.com/tidwall/cities v0.1.0/go.mod h1:lV/HDp2gCcRcHJWqgt6Di54GiDrTZwh1aG2ZUPNbqa4=
+github.com/tidwall/geoindex v1.7.0 h1:jtk41sfgwIt8MEDyC3xyKSj75iXXf6rjReJGDNPtR5o=
+github.com/tidwall/geoindex v1.7.0/go.mod h1:rvVVNEFfkJVWGUdEfU8QaoOg/9zFX0h9ofWzA60mz1I=
+github.com/tidwall/lotsa v1.0.2 h1:dNVBH5MErdaQ/xd9s769R31/n2dXavsQ0Yf4TMEHHw8=
+github.com/tidwall/lotsa v1.0.2/go.mod h1:X6NiU+4yHA3fE3Puvpnn1XMDrFZrE9JO2/w+UMuqgR8=
+github.com/tidwall/rtree v1.10.0 h1:+EcI8fboEaW1L3/9oW/6AMoQ8HiEIHyR7bQOGnmz4Mg=
+github.com/tidwall/rtree v1.10.0/go.mod h1:iDJQ9NBRtbfKkzZu02za+mIlaP+bjYPnunbSNidpbCQ=
 github.com/twpayne/go-geom v1.4.1 h1:LeivFqaGBRfyg0XJJ9pkudcptwhSSrYN9KZUW6HcgdA=
 github.com/twpayne/go-geom v1.4.1/go.mod h1:k/zktXdL+qnA6OgKsdEGUTA17jbQ2ZPTUa3CCySuGpE=
 github.com/twpayne/go-kml v1.5.2/go.mod h1:kz8jAiIz6FIdU2Zjce9qGlVtgFYES9vt7BTPBHf5jl4=
@@ -187,16 +195,16 @@ github.com/twpayne/go-polyline v1.1.1/go.mod h1:ybd9IWWivW/rlXPXuuckeKUyF3yrIim+
 github.com/twpayne/go-waypoint v0.0.0-20200706203930-b263a7f6e4e8/go.mod h1:qj5pHncxKhu9gxtZEYWypA/z097sxhFlbTyOyt9gcnU=
 golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
 golang.org/x/crypto v0.0.0-20200323165209-0ec3e9974c59/go.mod h1:LzIPMQfyMNhhGPhUkYOs5KpL4U8rLKemX1yGLhDgUto=
-golang.org/x/crypto v0.31.0 h1:ihbySMvVjLAeSH1IbfcRTkD/iNscyz8rGzjF/E5hV6U=
-golang.org/x/crypto v0.31.0/go.mod h1:kDsLvtWBEx7MV9tJOj9bnXsPbxwJQ6csT/x4KIN4Ssk=
+golang.org/x/crypto v0.24.0 h1:mnl8DM0o513X8fdIkmyFE/5hTYxbwYOjDS/+rK6qpRI=
+golang.org/x/crypto v0.24.0/go.mod h1:Z1PMYSOR5nyMcyAVAIQSKCDwalqy85Aqn1x3Ws4L5DM=
 golang.org/x/net v0.0.0-20190311183353-d8887717615a/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
 golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
 golang.org/x/net v0.0.0-20191003171128-d98b1b443823/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
-golang.org/x/net v0.33.0 h1:74SYHlV8BIgHIFC/LrYkOGIwL19eTYXQ5wc6TBuO36I=
-golang.org/x/net v0.33.0/go.mod h1:HXLR5J+9DxmrqMwG9qjGCxZ+zKXxBru04zlTvWlWuN4=
+golang.org/x/net v0.26.0 h1:soB7SVo0PWrY4vPW/+ay0jKDNScG2X9wFeYlXIvJsOQ=
+golang.org/x/net v0.26.0/go.mod h1:5YKkiSynbBIh3p6iOc/vibscux0x38BZDkn8sCUPxHE=
 golang.org/x/sync v0.0.0-20190423024810-112230192c58/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
-golang.org/x/sync v0.10.0 h1:3NQrjDixjgGwUOCaF8w2+VYHv0Ve/vGYSbdkTa98gmQ=
-golang.org/x/sync v0.10.0/go.mod h1:Czt+wKu1gCyEFDUtn0jG5QVvpJ6rzVqr5aXyt9drQfk=
+golang.org/x/sync v0.7.0 h1:YsImfSBoP9QPYL0xyKJPq0gcaJdG3rInoqxTWbfQu9M=
+golang.org/x/sync v0.7.0/go.mod h1:Czt+wKu1gCyEFDUtn0jG5QVvpJ6rzVqr5aXyt9drQfk=
 golang.org/x/sys v0.0.0-20180905080454-ebe1bf3edb33/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
@@ -210,8 +218,8 @@ golang.org/x/sys v0.12.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.30.0 h1:QjkSwP/36a20jFYWkSue1YwXzLmsV5Gfq7Eiy72C1uc=
 golang.org/x/sys v0.30.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
-golang.org/x/text v0.21.0 h1:zyQAAkrwaneQ066sspRyJaG9VNi/YJ1NfzcGB3hZ/qo=
-golang.org/x/text v0.21.0/go.mod h1:4IBbMaMmOPCJ8SecivzSH54+73PCFmPWxNTLm+vZkEQ=
+golang.org/x/text v0.16.0 h1:a94ExnEXNtEwYLGJSIUxnWoxoRz/ZcCsV63ROupILh4=
+golang.org/x/text v0.16.0/go.mod h1:GhwF1Be+LQoKShO3cGOHzqOgRrGaYc9AvblQOmPVHnI=
 golang.org/x/tools v0.0.0-20190624222133-a101b041ded4/go.mod h1:/rFqwRUd4F7ZHNgwSSTFct+R/Kf4OFW1sUzUTQQTgfc=
 golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543 h1:E7g+9GITq07hpfrRu66IVDexMakfv52eLZ2CXBWiKr4=
 golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=

tlxy/bbox.go

@@ -5,20 +5,23 @@ import (
 	"strings"
 )
 
+// BoundingBox is a simple bounding box.
 type BoundingBox struct {
 	MinLon float64 `json:"min_lon"`
 	MinLat float64 `json:"min_lat"`
 	MaxLon float64 `json:"max_lon"`
 	MaxLat float64 `json:"max_lat"`
 }
 
+// Contains returns true if the point is within the bounding box.
 func (v *BoundingBox) Contains(pt Point) bool {
 	if pt.Lon >= v.MinLon && pt.Lon <= v.MaxLon && pt.Lat >= v.MinLat && pt.Lat <= v.MaxLat {
 		return true
 	}
 	return false
 }
 
+// ParseBbox parses a bounding box from a string.
 func ParseBbox(v string) (BoundingBox, error) {
 	r := BoundingBox{}
 	if s := strings.Split(v, ","); len(s) == 4 {

tlxy/cut.go

@@ -4,7 +4,21 @@ import (
 	"math"
 )
 
-// SegmentClosestPoint returns the point (and position) on AB closest to P.
+// SegmentClosestPoint calculates the closest point on a line segment AB to a given point P,
+// and returns both the closest point and the distance to it.
+//
+// Given three points:
+//   - a: Start point of line segment
+//   - b: End point of line segment
+//   - p: Point to find closest position to
+//
+// Returns:
+//   - Point: The closest point on segment AB to point P
+//   - float64: The distance between point P and the closest point
+//
+// The algorithm first checks if P is closest to either endpoint.
+// If not, it projects P onto line AB and clamps the result to the segment.
+// Distance calculation assumes a simplified 2D Euclidean space suitable for small distances.
 func SegmentClosestPoint(a, b, p Point) (Point, float64) {
 	// ported from https://stackoverflow.com/questions/849211/shortest-distance-between-a-point-and-a-line-segment
 	// check ends
@@ -29,8 +43,26 @@ func SegmentClosestPoint(a, b, p Point) (Point, float64) {
 	return ret, Distance2d(ret, p)
 }
 
-// LineClosestPoint returns the point (and position) on line closest to point.
+// LineClosestPoint finds the nearest point on a line (represented as a slice of Points) to a given point.
 // Based on go-geom DistanceFromPointToLineString
+// It returns three values:
+// - The closest point on the line
+// - The index of the line segment containing the closest point (0-based)
+// - The normalized position along the line (0.0 to 1.0) where the closest point lies
+//
+// The line must contain at least 2 points. If the line has length 0 (single point or empty),
+// it returns the input point, index 0, and position 0.
+//
+// The calculation uses Haversine distance for geographic coordinates.
+//
+// Parameters:
+//   - line: A slice of Points representing the line segments
+//   - point: The reference Point to find the closest position to
+//
+// Returns:
+//   - Point: The closest point on the line
+//   - int: Index of the segment containing the closest point
+//   - float64: Normalized position along the line (0.0 to 1.0)
 func LineClosestPoint(line []Point, point Point) (Point, int, float64) {
 	position := 0.0
 	length := LengthHaversine(line)
@@ -60,8 +92,23 @@ func LineClosestPoint(line []Point, point Point) (Point, int, float64) {
 	return minp, minidx, position / length
 }
 
-// CutBetweenPoints attempts to cut a line based on the
-// relative positions of two nearby points projected onto the line.
+// CutBetweenPoints extracts a portion of a line between two points by finding the closest segments.
+// It takes a line (represented as a slice of Points), and two points (from and to) as input.
+// The function finds the closest segments to both input points and returns a new line that starts
+// at the projection of 'from' on its closest segment and ends at the projection of 'to' on its closest segment.
+// The returned line includes all original vertices between these segments.
+//
+// Parameters:
+//   - line: []Point - Input line as a slice of Points
+//   - from: Point - Starting point to cut from
+//   - to: Point - Ending point to cut to
+//
+// Returns:
+//   - []Point - A new slice of Points representing the cut portion of the original line
+//   - nil if the input line has fewer than 2 points
+//
+// Note: The function assumes the input points are relatively close to the line.
+// The search for the end point starts from the start point's segment to maintain proper ordering.
 func CutBetweenPoints(line []Point, from Point, to Point) []Point {
 	startPoint := Point{}
 	startNear := 1_000_000.0
@@ -95,23 +142,27 @@ func CutBetweenPoints(line []Point, from Point, to Point) []Point {
 	return coords
 }
 
-// func CutBetweenPoints(line []Point, startPoint Point, endPoint Point) []Point {
-// 	spt, sidx, _ := LineClosestPoint(line, startPoint)
-// 	ept, eidx, _ := LineClosestPoint(line, endPoint)
-// 	if eidx < sidx {
-// 		return nil
-// 	}
-// 	if DistanceHaversine(startPoint, spt) > 1000 || DistanceHaversine(endPoint, ept) > 1000 {
-// 		return nil
-// 	}
-// 	var ret []Point
-// 	ret = append(ret, spt)
-// 	ret = append(ret, line[sidx:eidx]...)
-// 	ret = append(ret, ept)
-// 	return ret
-// }
-
-// CutBetweenPositions is similar to CutBetweenPoints but takes absolute positions.
+// CutBetweenPositions returns a slice of points representing a segment of the input line
+// between the specified start and end distances along the line.
+//
+// The function takes a line represented as a slice of Points, a slice of cumulative distances
+// along the line (dists), and start/end distances (startDist, endDist) indicating where to cut.
+//
+// It returns a new slice containing:
+// - An interpolated point at startDist
+// - All original points between start and end positions
+// - An interpolated point at endDist
+//
+// Returns nil if the cut positions cannot be determined (e.g. distances out of range).
+//
+// Parameters:
+//   - line: Slice of Points representing the polyline
+//   - dists: Slice of cumulative distances along the line
+//   - startDist: Distance along the line where cut should start
+//   - endDist: Distance along the line where cut should end
+//
+// Returns:
+//   - Slice of Points representing the cut segment, or nil if cut is not possible
 func CutBetweenPositions(line []Point, dists []float64, startDist float64, endDist float64) []Point {
 	spt, ept, sidx, eidx, ok := cutBetweenPositions(line, dists, startDist, endDist)
 	if !ok {
@@ -124,7 +175,6 @@ func CutBetweenPositions(line []Point, dists []float64, startDist float64, endDi
 	return ret
 }
 
-// CutBetweenPositions is similar to CutBetweenPoints but takes absolute positions.
 func cutBetweenPositions(line []Point, dists []float64, startDist float64, endDist float64) (Point, Point, int, int, bool) {
 	for i := 0; i < len(dists)-1; i++ {
 		if startDist >= dists[i] && startDist <= dists[i+1] {

tlxy/line.go

@@ -2,8 +2,6 @@ package tlxy
 
 import (
 	"math"
-
-	"github.com/twpayne/go-polyline"
 )
 
 type Line []Point
@@ -13,27 +11,6 @@ type LineM struct {
 	Data   []float64
 }
 
-func DecodePolyline(p string) ([]Point, error) {
-	return DecodePolylineBytes([]byte(p))
-}
-
-func DecodePolylineBytes(p []byte) ([]Point, error) {
-	coords, _, err := polyline.DecodeCoords(p)
-	var ret []Point
-	for _, c := range coords {
-		ret = append(ret, Point{Lon: c[1], Lat: c[0]})
-	}
-	return ret, err
-}
-
-func EncodePolyline(coords []Point) []byte {
-	var g [][]float64
-	for _, c := range coords {
-		g = append(g, []float64{c.Lat, c.Lon})
-	}
-	return polyline.EncodeCoords(g)
-}
-
 // LineRelativePositionsFallback returns the relative position along the line for each point.
 // TODO: use Haversine
 func LineRelativePositionsFallback(line []Point) []float64 {

tlxy/line_test.go

@@ -2,8 +2,6 @@ package tlxy
 
 import (
 	"testing"
-
-	"github.com/stretchr/testify/assert"
 )
 
 func TestLineRelativePositions(t *testing.T) {
@@ -114,53 +112,6 @@ func TestContains(t *testing.T) {
 	}
 }
 
-func TestDecodePolyline(t *testing.T) {
-	check := "yfttIf{jR?B@BBDD?@ANDH@XHrAj@t@Z"
-	expect := []Point{
-		{Lon: -3.1738, Lat: 55.97821},
-		{Lon: -3.17382, Lat: 55.97821},
-		{Lon: -3.17384, Lat: 55.978199},
-		{Lon: -3.17387, Lat: 55.978179},
-		{Lon: -3.17387, Lat: 55.978149},
-		{Lon: -3.17386, Lat: 55.978139},
-		{Lon: -3.17389, Lat: 55.978059},
-		{Lon: -3.17390, Lat: 55.978009},
-		{Lon: -3.17395, Lat: 55.977879},
-		{Lon: -3.17417, Lat: 55.977459},
-		{Lon: -3.17431, Lat: 55.977189},
-	}
-	p, err := DecodePolyline(check)
-	if err != nil {
-		t.Fatal(err)
-	}
-	if len(expect) != len(p) {
-		t.Fatal("unequal length")
-	}
-	for i := range expect {
-		assert.InDelta(t, expect[i].Lon, p[i].Lon, 0.001)
-		assert.InDelta(t, expect[i].Lat, p[i].Lat, 0.001)
-	}
-}
-
-func TestEncodePolyline(t *testing.T) {
-	expect := "yfttIf{jR?B@BBDD?@ANDH@XHrAj@t@Z"
-	check := []Point{
-		{Lon: -3.1738, Lat: 55.97821},
-		{Lon: -3.17382, Lat: 55.97821},
-		{Lon: -3.17384, Lat: 55.978199},
-		{Lon: -3.17387, Lat: 55.978179},
-		{Lon: -3.17387, Lat: 55.978149},
-		{Lon: -3.17386, Lat: 55.978139},
-		{Lon: -3.17389, Lat: 55.978059},
-		{Lon: -3.17390, Lat: 55.978009},
-		{Lon: -3.17395, Lat: 55.977879},
-		{Lon: -3.17417, Lat: 55.977459},
-		{Lon: -3.17431, Lat: 55.977189},
-	}
-	p := EncodePolyline(check)
-	assert.Equal(t, expect, string(p))
-}
-
 func TestLineSimilarity(t *testing.T) {
 	// TODO
 	type testcase struct {