tests for GeoUtils

src/main/java/com/onthegomap/flatmap/OsmInputFile.java

@@ -32,18 +32,17 @@ public class OsmInputFile {
 
   public double[] getBounds() {
     try (var input = new FileInputStream(file)) {
-      var datinput = new DataInputStream(input);
-      int headersize = datinput.readInt();
-      if (headersize > 65536) {
-        throw new FileFormatException(
-          "Unexpectedly long header 65536 bytes. Possibly corrupt file " + file);
+      var dataInput = new DataInputStream(input);
+      int headerSize = dataInput.readInt();
+      if (headerSize > 65536) {
+        throw new FileFormatException("Unexpectedly long header 65536 bytes. Possibly corrupt file " + file);
       }
-      byte[] buf = datinput.readNBytes(headersize);
+      byte[] buf = dataInput.readNBytes(headerSize);
       BlobHeader header = BlobHeader.parseFrom(buf);
       if (!header.getType().equals("OSMHeader")) {
         throw new IllegalArgumentException("Expecting OSMHeader got " + header.getType());
       }
-      buf = datinput.readNBytes(header.getDatasize());
+      buf = dataInput.readNBytes(header.getDatasize());
       Blob blob = Blob.parseFrom(buf);
       ByteString data = null;
       if (blob.hasRaw()) {

src/main/java/com/onthegomap/flatmap/geo/GeoUtils.java

@@ -79,7 +79,8 @@ public class GeoUtils {
     }
   };
 
-  static final double QUANTIZED_WORLD_SIZE = Math.pow(2, 31);
+  private static final double QUANTIZED_WORLD_SIZE = Math.pow(2, 31);
+  private static final long LOWER_32_BIT_MASK = (1L << 32) - 1L;
 
   public static long encodeFlatLocation(double lon, double lat) {
     double worldX = getWorldX(lon);
@@ -88,4 +89,12 @@ public class GeoUtils {
     long y = (long) (worldY * QUANTIZED_WORLD_SIZE);
     return (x << 32) | y;
   }
+
+  public static double decodeWorldY(long encoded) {
+    return ((double) (encoded & LOWER_32_BIT_MASK)) / QUANTIZED_WORLD_SIZE;
+  }
+
+  public static double decodeWorldX(long encoded) {
+    return ((double) (encoded >> 32)) / QUANTIZED_WORLD_SIZE;
+  }
 }

src/main/java/com/onthegomap/flatmap/geo/TileCoord.java

@@ -8,13 +8,14 @@ public class TileCoord {
   private final int z;
 
   private TileCoord(int encoded, int x, int y, int z) {
+    assert z <= 14;
     this.encoded = encoded;
     this.x = x;
     this.y = y;
     this.z = z;
   }
 
-  public static TileCoord of(int x, int y, int z) {
+  public static TileCoord ofXYZ(int x, int y, int z) {
     return new TileCoord(encode(x, y, z), x, y, z);
   }
 

src/test/java/com/onthegomap/flatmap/GeoUtilsTest.java

@@ -1,5 +0,0 @@
-package com.onthegomap.flatmap;
-
-public class GeoUtilsTest {
-
-}

src/test/java/com/onthegomap/flatmap/TestUtils.java

@@ -4,6 +4,8 @@ import com.onthegomap.flatmap.geo.GeoUtils;
 import java.util.ArrayList;
 import java.util.List;
 import org.locationtech.jts.geom.Coordinate;
+import org.locationtech.jts.geom.CoordinateSequence;
+import org.locationtech.jts.geom.CoordinateXY;
 import org.locationtech.jts.geom.Geometry;
 import org.locationtech.jts.geom.GeometryCollection;
 import org.locationtech.jts.geom.MultiPoint;
@@ -11,6 +13,7 @@ import org.locationtech.jts.geom.MultiPolygon;
 import org.locationtech.jts.geom.Point;
 import org.locationtech.jts.geom.Polygon;
 import org.locationtech.jts.geom.util.AffineTransformation;
+import org.locationtech.jts.geom.util.GeometryTransformer;
 
 public class TestUtils {
 
@@ -20,7 +23,7 @@ public class TestUtils {
   public static List<Coordinate> newCoordinateList(double... coords) {
     List<Coordinate> result = new ArrayList<>(coords.length / 2);
     for (int i = 0; i < coords.length; i += 2) {
-      result.add(new Coordinate(coords[i], coords[i + 1]));
+      result.add(new CoordinateXY(coords[i], coords[i + 1]));
     }
     return result;
   }
@@ -30,7 +33,7 @@ public class TestUtils {
   }
 
   public static Point newPoint(double x, double y) {
-    return GeoUtils.gf.createPoint(new Coordinate(x, y));
+    return GeoUtils.gf.createPoint(new CoordinateXY(x, y));
   }
 
   public static MultiPoint newMultiPoint(Point... points) {
@@ -44,4 +47,19 @@ public class TestUtils {
   public static GeometryCollection newGeometryCollection(Geometry... geoms) {
     return GeoUtils.gf.createGeometryCollection(geoms);
   }
+
+  public static Geometry round(Geometry input) {
+    return new GeometryTransformer() {
+      @Override
+      protected CoordinateSequence transformCoordinates(
+        CoordinateSequence coords, Geometry parent) {
+        for (int i = 0; i < coords.size(); i++) {
+          for (int j = 0; j < coords.getDimension(); j++) {
+            coords.setOrdinate(i, j, Math.round(coords.getOrdinate(i, j) * 1e5) / 1e5);
+          }
+        }
+        return coords;
+      }
+    }.transform(input);
+  }
 }

src/test/java/com/onthegomap/flatmap/geo/GeoUtilsTest.java

@@ -0,0 +1,40 @@
+package com.onthegomap.flatmap.geo;
+
+import static com.onthegomap.flatmap.TestUtils.newPoint;
+import static com.onthegomap.flatmap.TestUtils.round;
+import static com.onthegomap.flatmap.geo.GeoUtils.ProjectWorldCoords;
+import static com.onthegomap.flatmap.geo.GeoUtils.decodeWorldX;
+import static com.onthegomap.flatmap.geo.GeoUtils.decodeWorldY;
+import static com.onthegomap.flatmap.geo.GeoUtils.encodeFlatLocation;
+import static com.onthegomap.flatmap.geo.GeoUtils.getWorldX;
+import static com.onthegomap.flatmap.geo.GeoUtils.getWorldY;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
+import org.locationtech.jts.geom.Geometry;
+import org.locationtech.jts.geom.Point;
+
+public class GeoUtilsTest {
+
+  @ParameterizedTest
+  @CsvSource({
+    "0,0, 0.5,0.5",
+    "0, -180, 0, 0.5",
+    "0, " + (180 - 1e-7) + ", 1, 0.5",
+    "45, 0, 0.5, 0.359725",
+    "-45, 0, 0.5, " + (1 - 0.359725)
+  })
+  public void testWorldCoords(double lat, double lon, double worldX, double worldY) {
+    assertEquals(worldY, getWorldY(lat), 1e-5);
+    assertEquals(worldX, getWorldX(lon), 1e-5);
+    long encoded = encodeFlatLocation(lon, lat);
+    assertEquals(worldY, decodeWorldY(encoded), 1e-5);
+    assertEquals(worldX, decodeWorldX(encoded), 1e-5);
+
+    Point input = newPoint(lon, lat);
+    Point expected = newPoint(worldX, worldY);
+    Geometry actual = ProjectWorldCoords.transform(input);
+    assertEquals(round(expected), round(actual));
+  }
+}

src/test/java/com/onthegomap/flatmap/geo/TileCoordTest.java

@@ -0,0 +1,34 @@
+package com.onthegomap.flatmap.geo;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
+
+public class TileCoordTest {
+
+  @ParameterizedTest
+  @CsvSource({
+    "0,0,0,0",
+    "0,0,1,268435456",
+    "0,1,1,268435457",
+    "1,1,1,268451841",
+    "100,100,14,-535232412",
+  })
+  public void testTileCoord(int x, int y, int z, int encoded) {
+    TileCoord coord1 = TileCoord.ofXYZ(x, y, z);
+    assertEquals(encoded, coord1.encoded());
+    TileCoord coord2 = TileCoord.decode(encoded);
+    assertEquals(coord1.x(), coord2.x());
+    assertEquals(coord1.y(), coord2.y());
+    assertEquals(coord1.z(), coord2.z());
+    assertEquals(coord1, coord2);
+  }
+
+  @Test
+  public void testThrowsPastZ14() {
+    assertThrows(AssertionError.class, () -> TileCoord.ofXYZ(0, 0, 15));
+  }
+}