add Tile.parentAtZoom

outerCoordinates holeCoordinates helpers for polygon and polygon coordinates
jillesvangurp · Feb 4, 2025 · 73413c5 · 73413c5
1 parent 46f6742
commit 73413c5
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Showing 6 changed files with 52 additions and 6 deletions.
diff --git a/src/commonMain/kotlin/com/jillesvangurp/geo/GeoHashUtils.kt b/src/commonMain/kotlin/com/jillesvangurp/geo/GeoHashUtils.kt
@@ -578,7 +578,7 @@ class GeoHashUtils {
             }
             if (includePartial) {
                 partiallyContained.forEach { hash ->
-                    decodeBbox(hash).polygon().coordinates?.get(0)?.let { ring ->
+                    decodeBbox(hash).polygon().outerCoordinates.let { ring ->
                         if (ring.firstOrNull { polygonContains(it, arrayOf(coordinates)) } != null) {
                             fullyContained.add(hash)
                         }

diff --git a/src/commonMain/kotlin/com/jillesvangurp/geo/tiles/Tile.kt b/src/commonMain/kotlin/com/jillesvangurp/geo/tiles/Tile.kt
@@ -250,5 +250,15 @@ fun Tile.parentTiles(): List<Tile> {
     return parentTiles
 }
 
+fun Tile.parentAtZoom(zoom: Int): Tile {
+    require(zoom in 0 until this.zoom) { "Target zoom must be less than current zoom ($this.zoom)" }
+
+    val scale = 1 shl (this.zoom - zoom)
+    val parentX = this.x / scale
+    val parentY = this.y / scale
+
+    return Tile(parentX, parentY, zoom)
+}
+
 fun PointCoordinates.tiles() =
     coordinateToTile(lat = this.latitude, lon = this.longitude, zoom = MAX_ZOOM).let { listOf(it) + it.parentTiles() }
diff --git a/src/commonMain/kotlin/com/jillesvangurp/geojson/geojson.kt b/src/commonMain/kotlin/com/jillesvangurp/geojson/geojson.kt
@@ -6,6 +6,7 @@ import com.jillesvangurp.geo.GeoGeometry
 import com.jillesvangurp.geo.GeoGeometry.Companion.ensureFollowsRightHandSideRule
 import com.jillesvangurp.geo.GeoGeometry.Companion.roundToDecimals
 import com.jillesvangurp.geo.GeoHashUtils
+import com.jillesvangurp.geojson.Geometry.Polygon
 import kotlinx.serialization.ExperimentalSerializationApi
 import kotlinx.serialization.Required
 import kotlinx.serialization.SerialName
@@ -31,6 +32,7 @@ typealias MultiPolygonCoordinates = Array<PolygonCoordinates>
  * BoundingBox = [westLongitude,southLatitude,eastLongitude,westLatitude]
  */
 typealias BoundingBox = DoubleArray
+
 fun BoundingBox.toGeometry(): Geometry.Polygon {
     val coordinates = arrayOf(
         arrayOf(
@@ -61,7 +63,8 @@ fun BoundingBox.contains(point: PointCoordinates): Boolean {
     return withinLongitude && withinLatitude
 }
 
-fun PolygonCoordinates.contains(point: PointCoordinates): Boolean = GeoGeometry.polygonContains(point.latitude,point.longitude, polygonCoordinatesPoints = this)
+fun PolygonCoordinates.contains(point: PointCoordinates): Boolean =
+    GeoGeometry.polygonContains(point.latitude, point.longitude, polygonCoordinatesPoints = this)
 
 fun Geometry.contains(point: PointCoordinates): Boolean {
     return when (this) {
@@ -141,30 +144,35 @@ fun Geometry.ensureHasAltitude(): Geometry = when (this) {
         if (this.coordinates?.size == 3) this
         else this.copy(coordinates = this.coordinates?.let { it + doubleArrayOf(0.0) })
     }
+
     is Geometry.MultiPoint -> {
         this.copy(coordinates = this.coordinates?.map {
             if (it.size == 3) it else it + doubleArrayOf(0.0)
         }?.toTypedArray())
     }
+
     is Geometry.LineString -> {
         this.copy(coordinates = this.coordinates?.map {
             if (it.size == 3) it else it + doubleArrayOf(0.0)
         }?.toTypedArray())
     }
+
     is Geometry.MultiLineString -> {
         this.copy(coordinates = this.coordinates?.map { line ->
             line.map {
                 if (it.size == 3) it else it + doubleArrayOf(0.0)
             }.toTypedArray()
         }?.toTypedArray())
     }
+
     is Geometry.Polygon -> {
         this.copy(coordinates = this.coordinates?.map { ring ->
             ring.map {
                 if (it.size == 3) it else it + doubleArrayOf(0.0)
             }.toTypedArray()
         }?.toTypedArray())
     }
+
     is Geometry.MultiPolygon -> {
         this.copy(coordinates = this.coordinates?.map { polygon ->
             polygon.map { ring ->
@@ -174,6 +182,7 @@ fun Geometry.ensureHasAltitude(): Geometry = when (this) {
             }.toTypedArray()
         }?.toTypedArray())
     }
+
     is Geometry.GeometryCollection -> {
         this.copy(geometries = this.geometries.map { it.ensureHasAltitude() }.toTypedArray())
     }
@@ -202,9 +211,11 @@ fun PointCoordinates.normalize(): PointCoordinates {
                 in 90.0..180.0 -> {
                     180.0 - lat
                 }
+
                 in -180.0..-90.0 -> {
                     -180.0 - lat
                 }
+
                 else -> {
                     lat
                 }
@@ -327,6 +338,7 @@ fun Geometry.asFeature(
 ): Feature {
     return Feature(this, properties, bbox)
 }
+
 fun Geometry.asFeatureWithProperties(
     bbox: BoundingBox? = null,
     propertiesBuilder: (JsonObjectBuilder.() -> Unit)
@@ -497,6 +509,7 @@ sealed class Geometry {
         override fun toString(): String = Json.encodeToString(Geometry.serializer(), this)
     }
 
+
     @Serializable
     @SerialName("MultiPolygon")
     data class MultiPolygon(
@@ -548,6 +561,13 @@ sealed class Geometry {
     }
 }
 
+val PolygonCoordinates.outerCoordinates get() = this[0]
+val PolygonCoordinates.holeCoordinates get() = this.slice(1..<this.size)
+
+val Polygon.outerCoordinates get() = coordinates?.outerCoordinates ?: error("no points found")
+val Polygon.holeCoordinates get() = coordinates?.holeCoordinates ?: error("no points found")
+
+
 @Serializable
 data class Feature(
     val geometry: Geometry?,

diff --git a/src/commonTest/kotlin/com/jillesvangurp/geo/tiles/TileTest.kt b/src/commonTest/kotlin/com/jillesvangurp/geo/tiles/TileTest.kt
@@ -4,6 +4,8 @@ import com.jillesvangurp.geo.tiles.Tile.Companion.coordinateToTile
 import com.jillesvangurp.geojson.contains
 import com.jillesvangurp.geojson.latitude
 import com.jillesvangurp.geojson.longitude
+import com.jillesvangurp.geojson.outerCoordinates
+import com.jillesvangurp.geojson.polygon
 import com.jillesvangurp.geojson.toGeometry
 import io.kotest.assertions.assertSoftly
 import io.kotest.assertions.withClue
@@ -19,8 +21,8 @@ import kotlin.test.Test
 fun randomTileCoordinate() =
     doubleArrayOf(Random.nextDouble(-180.0, 180.0), Random.nextDouble(Tile.MIN_LATITUDE, Tile.MAX_LATITUDE))
 
-fun randomTile(): Tile {
-    val zl = (0..22).random()
+fun randomTile(minZoom:Int=0): Tile {
+    val zl = (minZoom..22).random()
     val maxXY = 1 shl zl
     return Tile(
         x = (0 until maxXY).random(),
@@ -260,4 +262,17 @@ class TileTest {
             }
         }
     }
+
+    @Test
+    fun shouldBeContainedByParent() {
+        assertSoftly {
+            repeat(100) {
+                val tile = randomTile(5)
+                val parent = tile.parentAtZoom(tile.zoom - 3)
+                tile.bbox.polygon().outerCoordinates.forEach { point ->
+                    parent.bbox.contains(point) shouldBe true
+                }
+            }
+        }
+    }
 }
diff --git a/src/commonTest/kotlin/com/jillesvangurp/geogeometry/GeoHashUtilsTest.kt b/src/commonTest/kotlin/com/jillesvangurp/geogeometry/GeoHashUtilsTest.kt
@@ -9,6 +9,7 @@ import com.jillesvangurp.geojson.eastLongitude
 import com.jillesvangurp.geojson.latitude
 import com.jillesvangurp.geojson.longitude
 import com.jillesvangurp.geojson.northLatitude
+import com.jillesvangurp.geojson.outerCoordinates
 import com.jillesvangurp.geojson.polygon
 import com.jillesvangurp.geojson.southLatitude
 import com.jillesvangurp.geojson.westLongitude
@@ -119,7 +120,7 @@ class GeoHashUtilsTest {
       }            
         """.trimIndent()
         val p = DEFAULT_JSON.decodeFromString(Geometry.serializer(), concavePolygon) as Geometry.Polygon
-        val coordinates = p.coordinates?.get(0) ?: throw IllegalStateException()
+        val coordinates = p.outerCoordinates
         val hashes = GeoHashUtils.geoHashesForLinearRing(coordinates = coordinates, includePartial = true)
 
         println(hashes.size)

diff --git a/src/commonTest/kotlin/com/jillesvangurp/geogeometry/RotateScaleTranslateTest.kt b/src/commonTest/kotlin/com/jillesvangurp/geogeometry/RotateScaleTranslateTest.kt
@@ -24,7 +24,7 @@ class RotationTest {
         // we'll allow a few meters deviation. Earth is not perfectly spherical
         GeoGeometry.distance(oranienburgerTor, moved.centroid()) shouldBeLessThan 10.0
         moved as Geometry.Polygon
-        moved.coordinates?.get(0)!!.forEach {
+        moved.outerCoordinates.forEach {
             // radius of the circle should be similar, it will change a little
             val radius = GeoGeometry.distance(moved.centroid(), it)
             radius shouldBeGreaterThan 19.0