diff --git a/turf/src/commonMain/kotlin/io/github/dellisd/spatialk/turf/Transformation.kt b/turf/src/commonMain/kotlin/io/github/dellisd/spatialk/turf/Transformation.kt index 7d39438..b3244e9 100644 --- a/turf/src/commonMain/kotlin/io/github/dellisd/spatialk/turf/Transformation.kt +++ b/turf/src/commonMain/kotlin/io/github/dellisd/spatialk/turf/Transformation.kt @@ -1,7 +1,10 @@ package io.github.dellisd.spatialk.turf import io.github.dellisd.spatialk.geojson.LineString +import io.github.dellisd.spatialk.geojson.Point +import io.github.dellisd.spatialk.geojson.Polygon import io.github.dellisd.spatialk.geojson.Position +import kotlin.jvm.JvmOverloads /** * Takes a [LineString] and returns a curved version by applying a Bezier spline algorithm. @@ -14,7 +17,7 @@ import io.github.dellisd.spatialk.geojson.Position * @param sharpness a measure of how curvy the path should be between splines * @return A [LineString] containing a curved line around the positions of the input line */ -@OptIn(ExperimentalTurfApi::class) +@ExperimentalTurfApi public fun bezierSpline(line: LineString, duration: Int = 10_000, sharpness: Double = 0.85): LineString = LineString(bezierSpline(line.coordAll(), duration, sharpness)) @@ -134,3 +137,27 @@ public fun bezierSpline(coords: List, duration: Int = 10_000, sharpnes return positions } + +/** + * Takes a [Point] and calculates the circle polygon given a radius in degrees, radians, miles, or kilometers; and steps + * for precision. + * + * @param center center point of circle + * @param radius radius of the circle defined in [units] + * @param steps number of steps, must be at least four. Default is 64 + * @param units unit of [radius], default is [Units.Kilometers] + */ +@JvmOverloads +@ExperimentalTurfApi +public fun circle(center: Point, radius: Double, steps: Int = 64, units: Units = Units.Kilometers): Polygon { + require(steps >= 4) { "circle needs to have four or more coordinates." } + require(radius > 0) { "radius must be a positive value" } + val coordinates = (0..steps).map { step -> + destination(center.coordinates, radius, ((step * -360) / steps.toDouble()), units) + } + val ring = coordinates.plus(coordinates.first()) + return Polygon( + coordinates = listOf(ring), + bbox = computeBbox(ring) + ) +} \ No newline at end of file diff --git a/turf/src/commonTest/kotlin/io/github/dellisd/spatialk/turf/TransformationTest.kt b/turf/src/commonTest/kotlin/io/github/dellisd/spatialk/turf/TransformationTest.kt index 2843f1e..9e09c25 100644 --- a/turf/src/commonTest/kotlin/io/github/dellisd/spatialk/turf/TransformationTest.kt +++ b/turf/src/commonTest/kotlin/io/github/dellisd/spatialk/turf/TransformationTest.kt @@ -1,8 +1,12 @@ package io.github.dellisd.spatialk.turf import io.github.dellisd.spatialk.geojson.Feature +import io.github.dellisd.spatialk.geojson.FeatureCollection import io.github.dellisd.spatialk.geojson.LineString +import io.github.dellisd.spatialk.geojson.Point import io.github.dellisd.spatialk.turf.utils.readResource +import kotlinx.serialization.json.double +import kotlinx.serialization.json.jsonPrimitive import kotlin.test.Test import kotlin.test.assertEquals @@ -37,4 +41,19 @@ class TransformationTest { assertEquals(expectedOut.geometry, bezierSpline(feature.geometry as LineString)) } + + @Test + fun testCircle() { + val point = Feature.fromJson(readResource("transformation/circle/in/circle1.json")) + val expectedOut = FeatureCollection.fromJson(readResource("transformation/circle/out/circle1.json")) + + val (_, expectedCircle) = expectedOut.features + + val circle = circle( + center = point.geometry as Point, + radius = point.properties["radius"]?.jsonPrimitive?.double ?: 0.0, + ) + + assertEquals(expectedCircle.geometry, circle) + } } diff --git a/turf/src/commonTest/resources/transformation/circle/in/circle1.json b/turf/src/commonTest/resources/transformation/circle/in/circle1.json new file mode 100644 index 0000000..119ffc0 --- /dev/null +++ b/turf/src/commonTest/resources/transformation/circle/in/circle1.json @@ -0,0 +1,10 @@ +{ + "type": "Feature", + "properties": { + "radius": 5 + }, + "geometry": { + "type": "Point", + "coordinates": [-75.343, 39.984] + } +} diff --git a/turf/src/commonTest/resources/transformation/circle/out/circle1.json b/turf/src/commonTest/resources/transformation/circle/out/circle1.json new file mode 100644 index 0000000..755f544 --- /dev/null +++ b/turf/src/commonTest/resources/transformation/circle/out/circle1.json @@ -0,0 +1,299 @@ +{ + "type": "FeatureCollection", + "features": [ + { + "type": "Feature", + "geometry": { + "type": 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