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Posted to dev@sedona.apache.org by "jiayuasu (via GitHub)" <gi...@apache.org> on 2023/05/20 09:11:20 UTC

[GitHub] [sedona] jiayuasu opened a new pull request, #835: [SEDONA-281] Support geodesic / geography functions

jiayuasu opened a new pull request, #835:
URL: https://github.com/apache/sedona/pull/835

   
   ## Did you read the Contributor Guide?
   
   - Yes, I have read [Contributor Rules](https://sedona.apache.org/latest-snapshot/community/rule/) and [Contributor Development Guide](https://sedona.apache.org/latest-snapshot/community/develop/)
   
   ## Is this PR related to a JIRA ticket?
   
   - Yes, the URL of the associated JIRA ticket is https://issues.apache.org/jira/browse/SEDONA-281. The PR name follows the format `[SEDONA-281] my subject`.
   
   
   ## What changes were proposed in this PR?
   
   ### ST_AreaSpheroid
   
   Return the geodesic area of A using WGS84 spheroid. Unit is meter. Works better for large geometries (country level) compared to `ST_Area` + `ST_Transform`. It is equivalent to PostGIS `ST_Area(geography, use_spheroid=true)` function and produces nearly identical results.
   
   ### ST_LengthSpheroid
   
   Return the geodesic perimeter of A using WGS84 spheroid. Unit is meter. Works better for large geometries (country level) compared to `ST_Length` + `ST_Transform`. It is equivalent to PostGIS `ST_Length(geography, use_spheroid=true)` and `ST_LengthSpheroid` function and produces nearly identical results.
   
   ### ST_DistanceSphere
   
   Return the haversine / great-circle distance of A using a given earth radius (default radius: 6378137.0). Unit is meter. Works better for large geometries (country level) compared to `ST_Distance` + `ST_Transform`. It is equivalent to PostGIS `ST_Distance(geography, use_spheroid=false)` and `ST_DistanceSphere` function and produces nearly identical results. It provides faster but less accurate result compared to `ST_DistanceSpheroid`.
   
   ### ST_DistanceSpheroid
   
   Return the geodesic distance of A using WGS84 spheroid. Unit is meter. Works better for large geometries (country level) compared to `ST_Distance` + `ST_Transform`. It is equivalent to PostGIS `ST_Distance(geography, use_spheroid=true)` and `ST_DistanceSpheroid` function and produces nearly identical results. It provides slower but more accurate result compared to `ST_DistanceSphere`.
   
   ## How was this patch tested?
   
   Added many unit tests.
   
   ## Did this PR include necessary documentation updates?
   
   - Yes, I am adding a new API. I am using the [current SNAPSHOT version number](https://github.com/apache/sedona/blob/master/pom.xml#L29) in since `vX.Y.Z` format.
   


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[GitHub] [sedona] jiayuasu merged pull request #835: [SEDONA-281] Support geodesic / geography functions

Posted by "jiayuasu (via GitHub)" <gi...@apache.org>.
jiayuasu merged PR #835:
URL: https://github.com/apache/sedona/pull/835


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[GitHub] [sedona] Kontinuation commented on a diff in pull request #835: [SEDONA-281] Support geodesic / geography functions

Posted by "Kontinuation (via GitHub)" <gi...@apache.org>.
Kontinuation commented on code in PR #835:
URL: https://github.com/apache/sedona/pull/835#discussion_r1209188035


##########
common/src/main/java/org/apache/sedona/common/sphere/Haversine.java:
##########
@@ -0,0 +1,65 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+package org.apache.sedona.common.sphere;
+
+import org.locationtech.jts.geom.Coordinate;
+import org.locationtech.jts.geom.Geometry;
+
+import static java.lang.Math.atan2;
+import static java.lang.Math.cos;
+import static java.lang.Math.sin;
+import static java.lang.Math.sqrt;
+import static java.lang.Math.toRadians;
+
+public class Haversine
+{
+    /**
+     * Calculate the distance between two points on the earth using the "haversine" formula.
+     * This is also known as the great-circle distance
+     * This will produce almost identical result to PostGIS ST_DistanceSphere and
+     * ST_Distance(useSpheroid=false)
+     * @param geom1 The first geometry. Each coordinate is in lat/lon order
+     * @param geom2 The second geometry. Each coordinate is in lat/lon order
+     * @return
+     */
+    public static double distance(Geometry geom1, Geometry geom2, double AVG_EARTH_RADIUS)
+    {
+        Coordinate coordinate1 = geom1.getGeometryType().equals("Point")? geom1.getCoordinate():geom1.getCentroid().getCoordinate();
+        Coordinate coordinate2 = geom2.getGeometryType().equals("Point")? geom2.getCoordinate():geom2.getCentroid().getCoordinate();
+        // Calculate the distance between the two points
+        double lat1 = coordinate1.getX();
+        double lon1 = coordinate1.getY();
+        double lat2 = coordinate2.getX();
+        double lon2 = coordinate2.getY();
+        double latDistance = toRadians(lat2 - lat1);
+        double lngDistance = toRadians(lon2 - lon1);
+        double a = sin(latDistance / 2) * sin(latDistance / 2)
+                + cos(toRadians(lat1)) * cos(toRadians(lat2))
+                * sin(lngDistance / 2) * sin(lngDistance / 2);
+        double c = 2 * atan2(sqrt(a), sqrt(1 - a));
+        return AVG_EARTH_RADIUS * c * 1.0;
+    }
+
+    // Calculate the distance between two points on the earth using the "haversine" formula.
+    // The radius of the earth is 6371.0 km
+    public static double distance(Geometry geom1, Geometry geom2)
+    {
+        return distance(geom1, geom2, 6378137.0);

Review Comment:
   I suggest using `6371008` as the default radius according to [PostGIS ST_DistanceSphere](https://postgis.net/docs/ST_DistanceSphere.html) and https://en.wikipedia.org/wiki/Earth_radius 



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