Fix an edge case that the point goes outside of visible point

server/src/main/java/au/org/aodn/ogcapi/server/core/util/BboxUtils.java

@@ -19,24 +19,30 @@ public class BboxUtils {
      * @return - Geometry which is bounded [-180, 180]
      */
     public static MultiPolygon normalizeBbox(double minx, double maxx, double miny, double maxy) {
-        // Bounding check, if greater than 360 already cover whole world, so adjust the maxx to something
-        // meaningful, noted that minx and maxx is not normalized yet so can be anything even beyond 180
-        if((maxx - minx) >= 360) {
-            // Value does not matter, it covered whole world which is equal to
+        // A span of 360 or more covers the whole world. Incoming longitudes may sit outside [-180, 180].
+        if ((maxx - minx) >= 360) {
             minx = -180;
             maxx = 180;
+        } else {
+            // Shift into one 360-degree window with minx in [-180, 180). A viewport that
+            // continues past the date line (for example 112 to 188.9) then has maxx > 180,
+            // and the wrapped east edge is maxx - 360 (188.9 -> -171.1), not -(maxx - 180).
+            while (minx < -180) {
+                minx += 360;
+                maxx += 360;
+            }
+            while (minx >= 180) {
+                minx -= 360;
+                maxx -= 360;
+            }
         }
-        minx = (minx < -180) ? 180 - Math.abs(180 + minx) : minx;
-        maxx = (maxx > 180) ? -(maxx - 180) : maxx;
-        // Normalized the box, so it is within [-180, 180]
+
         List<Polygon> polygons = new ArrayList<>();
-        if(maxx >= 0 && maxx <= 180) {
-            // Normal case
-            polygons.add((Polygon)createBoxPolygon(minx, maxx, miny, maxy));
-        }
-        else {
-            polygons.add((Polygon)createBoxPolygon(minx, 180, miny, maxy));
-            polygons.add((Polygon)createBoxPolygon(-180, maxx, miny, maxy));
+        if (maxx <= 180) {
+            polygons.add((Polygon) createBoxPolygon(minx, maxx, miny, maxy));
+        } else {
+            polygons.add((Polygon) createBoxPolygon(minx, 180, miny, maxy));
+            polygons.add((Polygon) createBoxPolygon(-180, maxx - 360, miny, maxy));
         }
         return GeometryUtils.getFactory().createMultiPolygon(polygons.toArray(new Polygon[0]));
     }

server/src/test/java/au/org/aodn/ogcapi/server/common/RestApiTest.java

@@ -855,10 +855,10 @@ public void verifyCentroidCalIsCorrect() throws IOException {
         cacheNoLandGeometry.evictAllNoLandGeometry();
 
         String expected = """
-                {"links":[],"collections":[{"properties":{"centroid":[[129.19579,-33.09197]]},"id":"097a5435-91f4-4730-90aa-ddae94afcbda","links":[],"itemType":"Collection"}],"total":1,"search_after":["0.0","str:097a5435-91f4-4730-90aa-ddae94afcbda"]}""";
+               {"links":[],"collections":[{"properties":{"centroid":[[166.75446,-27.62500]]},"id":"097a5435-91f4-4730-90aa-ddae94afcbda","links":[],"itemType":"Collection"}],"total":1,"search_after":["0.0","str:097a5435-91f4-4730-90aa-ddae94afcbda"]}""";
 
         ResponseEntity<String> collections = testRestTemplate.exchange(
-                getBasePath() + "/collections?properties=id,centroid&q=097a5435-91f4-4730-90aa-ddae94afcbda&filter=page_size=800 AND BBOX(geometry,117.21720908167362,-34.63803401514584,149.78279091832303,-16.36196598484962)&sortby=id",
+                getBasePath() + "/collections?properties=id,centroid&q=097a5435-91f4-4730-90aa-ddae94afcbda&filter=page_size=800 AND BBOX(geometry,112.03097102449121,-50.499567507281824,188.89962377189153,-4.6416246696196195)&sortby=id",
                 HttpMethod.GET,
                 null,
                 new ParameterizedTypeReference<>() {});

server/src/test/java/au/org/aodn/ogcapi/server/core/util/BboxUtilsTest.java

@@ -1,14 +1,22 @@
 package au.org.aodn.ogcapi.server.core.util;
 
+import org.junit.jupiter.api.Assertions;
 import org.junit.jupiter.api.Test;
 import org.locationtech.jts.geom.Geometry;
 import org.locationtech.jts.geom.Polygon;
 
+import java.math.BigDecimal;
+import java.util.List;
+import java.util.Map;
+
+import static au.org.aodn.ogcapi.server.BaseTestClass.readResourceFile;
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 public class BboxUtilsTest {
     /**
-     * This test have bbox start from -4.6 -> 0 -> 180 -> -180 -> -76.5
+     * East edge 314.173 wraps to 314.173 - 360 = -45.827, so the box runs
+     * -4.6 -> 180 and -180 -> -45.827.
      */
     @Test
     public void verifyNormalizeBbox1() {
@@ -18,11 +26,11 @@ public void verifyNormalizeBbox1() {
         Polygon expect1 = (Polygon)BboxUtils.createBoxPolygon(-4.614697916267209, 180, -76.58044236400484, 60.83962132913365);
         assertEquals(expect1, n.getGeometryN(0), "First polygon");
 
-        Polygon expect3 = (Polygon)BboxUtils.createBoxPolygon(-180, -134.17320304524225, -76.58044236400484, 60.83962132913365);
+        Polygon expect3 = (Polygon)BboxUtils.createBoxPolygon(-180, -45.826796954757754, -76.58044236400484, 60.83962132913365);
         assertEquals(expect3, n.getGeometryN(1), "Second polygon");
     }
     /**
-     * This test have bbox start from 10 -> 180 -> -180 -> -76.5
+     * East edge 314.173 wraps to -45.827, so the box runs 10 -> 180 and -180 -> -45.827.
      */
     @Test
     public void verifyNormalizeBbox2() {
@@ -32,7 +40,7 @@ public void verifyNormalizeBbox2() {
         Polygon expect1 = (Polygon)BboxUtils.createBoxPolygon(10, 180, -76.58044236400484, 60.83962132913365);
         assertEquals(expect1, n.getGeometryN(0), "First polygon");
 
-        Polygon expect2 = (Polygon)BboxUtils.createBoxPolygon(-180, -134.17320304524225, -76.58044236400484, 60.83962132913365);
+        Polygon expect2 = (Polygon)BboxUtils.createBoxPolygon(-180, -45.826796954757754, -76.58044236400484, 60.83962132913365);
         assertEquals(expect2, n.getGeometryN(1), "Second polygon");
     }
     /**
@@ -102,4 +110,57 @@ public void verifyNormalizeBboxVerySmallMinX() {
         Polygon expect1 = (Polygon)BboxUtils.createBoxPolygon(-180, 180, -76.58044236400484, 60.83962132913365);
         assertEquals(expect1, n.getGeometryN(0), "First polygon min 10");
     }
+
+    /**
+     * A map viewport of 112.03 to 188.90 continues only ~9 degrees past the date line.
+     */
+    @Test
+    public void verifyNormalizeBboxViewportPastDateline() {
+        double minx = 112.03097102449121;
+        double maxx = 188.89962377189153;
+        double miny = -50.499567507281824;
+        double maxy = -4.6416246696196195;
+        Geometry n = BboxUtils.normalizeBbox(minx, maxx, miny, maxy);
+        assertEquals(2, n.getNumGeometries(), "Size correct");
+
+        Polygon eastOfAustralia = (Polygon) BboxUtils.createBoxPolygon(minx, 180, miny, maxy);
+        assertEquals(eastOfAustralia, n.getGeometryN(0), "First polygon");
+
+        Polygon pastDateline = (Polygon) BboxUtils.createBoxPolygon(-180, -171.10037622810847, miny, maxy);
+        assertEquals(pastDateline, n.getGeometryN(1), "Second polygon");
+    }
+
+    @Test
+    public void verifyNormalizeBboxWestOfGreenwichStaysOnePolygon() {
+        Geometry n = BboxUtils.normalizeBbox(-20, -10, -5, 5);
+        assertEquals(1, n.getNumGeometries(), "Size correct");
+        Polygon expect = (Polygon) BboxUtils.createBoxPolygon(-20, -10, -5, 5);
+        assertEquals(expect, n.getGeometryN(0), "West box");
+    }
+
+    /**
+     * OBIS no-land geometry crosses the date line. The centroid of the visible clip must sit in the viewport.
+     */
+    @Test
+    public void verifyObisCentroidInsideViewport() throws Exception {
+        String json = readResourceFile("classpath:databag/097a5435-91f4-4730-90aa-ddae94afcbda.json");
+        @SuppressWarnings("unchecked")
+        Map<String, Object> record = GeometryUtils.getMapper().readValue(json, Map.class);
+        @SuppressWarnings("unchecked")
+        Map<String, Object> summaries = (Map<String, Object>) record.get("summaries");
+        Geometry noLand = GeometryUtils.readGeometry(summaries.get("proj:geometry_noland")).orElseThrow();
+
+        double minx = 112.03097102449121;
+        double maxx = 188.89962377189153;
+        double miny = -50.499567507281824;
+        double maxy = -4.6416246696196195;
+        Geometry visible = noLand.intersection(BboxUtils.normalizeBbox(minx, maxx, miny, maxy));
+        List<List<BigDecimal>> centroid = GeometryUtils.createCentroid(visible);
+        Assertions.assertNotNull(centroid);
+        assertEquals(1, centroid.size(), "One centroid");
+        double x = centroid.get(0).get(0).doubleValue();
+        double y = centroid.get(0).get(1).doubleValue();
+        boolean inView = y >= miny && y <= maxy && ((x >= minx && x <= 180) || (x >= -180 && x <= maxx - 360));
+        assertTrue(inView, "centroid " + centroid + " outside viewport");
+    }
 }