diff --git a/src/Feature/Feature.php b/src/Feature/Feature.php
index 4d67554..b6ad2d9 100644
--- a/src/Feature/Feature.php
+++ b/src/Feature/Feature.php
@@ -18,7 +18,7 @@
  */
 class Feature extends GeoJson
 {
-    protected string $type = 'Feature';
+    protected string $type = self::TYPE_FEATURE;
 
     protected ?Geometry $geometry;
 
diff --git a/src/Feature/FeatureCollection.php b/src/Feature/FeatureCollection.php
index f8babc8..87efacb 100644
--- a/src/Feature/FeatureCollection.php
+++ b/src/Feature/FeatureCollection.php
@@ -26,7 +26,7 @@
  */
 class FeatureCollection extends GeoJson implements Countable, IteratorAggregate
 {
-    protected string $type = 'FeatureCollection';
+    protected string $type = self::TYPE_FEATURE_COLLECTION;
 
     /**
      * @var array<Feature>
diff --git a/src/GeoJson.php b/src/GeoJson.php
index ba3aa75..5f82dcb 100644
--- a/src/GeoJson.php
+++ b/src/GeoJson.php
@@ -23,6 +23,16 @@
  */
 abstract class GeoJson implements JsonSerializable, JsonUnserializable
 {
+    public const TYPE_LINE_STRING = 'LineString';
+    public const TYPE_MULTI_LINE_STRING = 'MultiLineString';
+    public const TYPE_MULTI_POINT = 'MultiPoint';
+    public const TYPE_MULTI_POLYGON = 'MultiPolygon';
+    public const TYPE_POINT = 'Point';
+    public const TYPE_POLYGON = 'Polygon';
+    public const TYPE_FEATURE = 'Feature';
+    public const TYPE_FEATURE_COLLECTION = 'FeatureCollection';
+    public const TYPE_GEOMETRY_COLLECTION = 'GeometryCollection';
+
     protected ?BoundingBox $boundingBox = null;
 
     protected ?CoordinateReferenceSystem $crs = null;
@@ -87,12 +97,12 @@ final public static function jsonUnserialize($json): self
         $args = [];
 
         switch ($type) {
-            case 'LineString':
-            case 'MultiLineString':
-            case 'MultiPoint':
-            case 'MultiPolygon':
-            case 'Point':
-            case 'Polygon':
+            case self::TYPE_LINE_STRING:
+            case self::TYPE_MULTI_LINE_STRING:
+            case self::TYPE_MULTI_POINT:
+            case self::TYPE_MULTI_POLYGON:
+            case self::TYPE_POINT:
+            case self::TYPE_POLYGON:
                 if (! $json->offsetExists('coordinates')) {
                     throw UnserializationException::missingProperty($type, 'coordinates', 'array');
                 }
@@ -104,7 +114,7 @@ final public static function jsonUnserialize($json): self
                 $args[] = $json['coordinates'];
                 break;
 
-            case 'Feature':
+            case self::TYPE_FEATURE:
                 $geometry = $json['geometry'] ?? null;
                 $properties = $json['properties'] ?? null;
                 $id = $json['id'] ?? null;
@@ -124,7 +134,7 @@ final public static function jsonUnserialize($json): self
                 $args[] = $id;
                 break;
 
-            case 'FeatureCollection':
+            case self::TYPE_FEATURE_COLLECTION:
                 if (! $json->offsetExists('features')) {
                     throw UnserializationException::missingProperty($type, 'features', 'array');
                 }
@@ -136,7 +146,7 @@ final public static function jsonUnserialize($json): self
                 $args[] = array_map([self::class, 'jsonUnserialize'], $json['features']);
                 break;
 
-            case 'GeometryCollection':
+            case self::TYPE_GEOMETRY_COLLECTION:
                 if (! $json->offsetExists('geometries')) {
                     throw UnserializationException::missingProperty($type, 'geometries', 'array');
                 }
diff --git a/src/Geometry/GeometryCollection.php b/src/Geometry/GeometryCollection.php
index b813f43..d50387f 100644
--- a/src/Geometry/GeometryCollection.php
+++ b/src/Geometry/GeometryCollection.php
@@ -25,7 +25,7 @@
  */
 class GeometryCollection extends Geometry implements Countable, IteratorAggregate
 {
-    protected string $type = 'GeometryCollection';
+    protected string $type = self::TYPE_GEOMETRY_COLLECTION;
 
     /**
      * @var array<Geometry>
diff --git a/src/Geometry/LineString.php b/src/Geometry/LineString.php
index a230df9..4058712 100644
--- a/src/Geometry/LineString.php
+++ b/src/Geometry/LineString.php
@@ -20,7 +20,7 @@
  */
 class LineString extends MultiPoint
 {
-    protected string $type = 'LineString';
+    protected string $type = self::TYPE_LINE_STRING;
 
     /**
      * @param array<Point|array<float|int>> $positions
diff --git a/src/Geometry/MultiLineString.php b/src/Geometry/MultiLineString.php
index 4fd3aa1..d267e0a 100644
--- a/src/Geometry/MultiLineString.php
+++ b/src/Geometry/MultiLineString.php
@@ -19,7 +19,7 @@
  */
 class MultiLineString extends Geometry
 {
-    protected string $type = 'MultiLineString';
+    protected string $type = self::TYPE_MULTI_LINE_STRING;
 
     /**
      * @param array<LineString|array<Point|array<int|float>>> $lineStrings
diff --git a/src/Geometry/MultiPoint.php b/src/Geometry/MultiPoint.php
index e84731e..65bdbbf 100644
--- a/src/Geometry/MultiPoint.php
+++ b/src/Geometry/MultiPoint.php
@@ -19,7 +19,7 @@
  */
 class MultiPoint extends Geometry
 {
-    protected string $type = 'MultiPoint';
+    protected string $type = self::TYPE_MULTI_POINT;
 
     /**
      * @param array<Point|array<float|int>> $positions
diff --git a/src/Geometry/MultiPolygon.php b/src/Geometry/MultiPolygon.php
index 9ea247a..dc51292 100644
--- a/src/Geometry/MultiPolygon.php
+++ b/src/Geometry/MultiPolygon.php
@@ -19,7 +19,7 @@
  */
 class MultiPolygon extends Geometry
 {
-    protected string $type = 'MultiPolygon';
+    protected string $type = self::TYPE_MULTI_POLYGON;
 
     /**
      * @param array<Polygon|array<LinearRing|array<Point|array<int|float>>>> $polygons
diff --git a/src/Geometry/Point.php b/src/Geometry/Point.php
index 75ad66f..0a3c38d 100644
--- a/src/Geometry/Point.php
+++ b/src/Geometry/Point.php
@@ -22,7 +22,7 @@
  */
 class Point extends Geometry
 {
-    protected string $type = 'Point';
+    protected string $type = self::TYPE_POINT;
 
     /**
      * @param array<float|int> $position
diff --git a/src/Geometry/Polygon.php b/src/Geometry/Polygon.php
index f60c98d..aaf0259 100644
--- a/src/Geometry/Polygon.php
+++ b/src/Geometry/Polygon.php
@@ -17,7 +17,7 @@
  */
 class Polygon extends Geometry
 {
-    protected string $type = 'Polygon';
+    protected string $type = self::TYPE_POLYGON;
 
     /**
      * @param array<LinearRing|array<Point|array<int|float>>> $linearRings
diff --git a/tests/Feature/FeatureCollectionTest.php b/tests/Feature/FeatureCollectionTest.php
index 4c3b61d..8d3d3d4 100644
--- a/tests/Feature/FeatureCollectionTest.php
+++ b/tests/Feature/FeatureCollectionTest.php
@@ -92,11 +92,11 @@ public function testSerialization(): void
         $collection = new FeatureCollection($features);
 
         $expected = [
-            'type' => 'FeatureCollection',
+            'type' => GeoJson::TYPE_FEATURE_COLLECTION,
             'features' => [['feature1'], ['feature2']],
         ];
 
-        $this->assertSame('FeatureCollection', $collection->getType());
+        $this->assertSame(GeoJson::TYPE_FEATURE_COLLECTION, $collection->getType());
         $this->assertSame($features, $collection->getFeatures());
         $this->assertSame($expected, $collection->jsonSerialize());
     }
@@ -127,21 +127,21 @@ public function testUnserialization($assoc): void
         $collection = GeoJson::jsonUnserialize($json);
 
         $this->assertInstanceOf(FeatureCollection::class, $collection);
-        $this->assertSame('FeatureCollection', $collection->getType());
+        $this->assertSame(GeoJson::TYPE_FEATURE_COLLECTION, $collection->getType());
         $this->assertCount(1, $collection);
 
         $features = iterator_to_array($collection);
         $feature = $features[0];
 
         $this->assertInstanceOf(Feature::class, $feature);
-        $this->assertSame('Feature', $feature->getType());
+        $this->assertSame(GeoJson::TYPE_FEATURE, $feature->getType());
         $this->assertSame('test.feature.1', $feature->getId());
         $this->assertNull($feature->getProperties());
 
         $geometry = $feature->getGeometry();
 
         $this->assertInstanceOf(Point::class, $geometry);
-        $this->assertSame('Point', $geometry->getType());
+        $this->assertSame(GeoJson::TYPE_POINT, $geometry->getType());
         $this->assertSame([1, 1], $geometry->getCoordinates());
     }
 
@@ -158,7 +158,7 @@ public function testUnserializationShouldRequireFeaturesProperty(): void
         $this->expectException(UnserializationException::class);
         $this->expectExceptionMessage('FeatureCollection expected "features" property of type array, none given');
 
-        GeoJson::jsonUnserialize(['type' => 'FeatureCollection']);
+        GeoJson::jsonUnserialize(['type' => GeoJson::TYPE_FEATURE_COLLECTION]);
     }
 
     public function testUnserializationShouldRequireFeaturesArray(): void
@@ -166,6 +166,6 @@ public function testUnserializationShouldRequireFeaturesArray(): void
         $this->expectException(UnserializationException::class);
         $this->expectExceptionMessage('FeatureCollection expected "features" property of type array');
 
-        GeoJson::jsonUnserialize(['type' => 'FeatureCollection', 'features' => null]);
+        GeoJson::jsonUnserialize(['type' => GeoJson::TYPE_FEATURE_COLLECTION, 'features' => null]);
     }
 }
diff --git a/tests/Feature/FeatureTest.php b/tests/Feature/FeatureTest.php
index 7c3ec00..b3a5d9f 100644
--- a/tests/Feature/FeatureTest.php
+++ b/tests/Feature/FeatureTest.php
@@ -37,13 +37,13 @@ public function testSerialization(): void
         $feature = new Feature($geometry, $properties, $id);
 
         $expected = [
-            'type' => 'Feature',
+            'type' => GeoJson::TYPE_FEATURE,
             'geometry' => ['geometry'],
             'properties' => $properties,
             'id' => 'identifier',
         ];
 
-        $this->assertSame('Feature', $feature->getType());
+        $this->assertSame(GeoJson::TYPE_FEATURE, $feature->getType());
         $this->assertSame($geometry, $feature->getGeometry());
         $this->assertSame($id, $feature->getId());
         $this->assertSame($properties, $feature->getProperties());
@@ -55,7 +55,7 @@ public function testSerializationWithNullConstructorArguments(): void
         $feature = new Feature();
 
         $expected = [
-            'type' => 'Feature',
+            'type' => GeoJson::TYPE_FEATURE,
             'geometry' => null,
             'properties' => null,
         ];
@@ -68,7 +68,7 @@ public function testSerializationShouldConvertEmptyPropertiesArrayToObject(): vo
         $feature = new Feature(null, []);
 
         $expected = [
-            'type' => 'Feature',
+            'type' => GeoJson::TYPE_FEATURE,
             'geometry' => null,
             'properties' => new stdClass(),
         ];
@@ -100,14 +100,14 @@ public function testUnserialization($assoc): void
         $feature = GeoJson::jsonUnserialize($json);
 
         $this->assertInstanceOf(Feature::class, $feature);
-        $this->assertSame('Feature', $feature->getType());
+        $this->assertSame(GeoJson::TYPE_FEATURE, $feature->getType());
         $this->assertSame('test.feature.1', $feature->getId());
         $this->assertSame(['key' => 'value'], $feature->getProperties());
 
         $geometry = $feature->getGeometry();
 
         $this->assertInstanceOf(Point::class, $geometry);
-        $this->assertSame('Point', $geometry->getType());
+        $this->assertSame(GeoJson::TYPE_POINT, $geometry->getType());
         $this->assertSame([1, 1], $geometry->getCoordinates());
     }
 
diff --git a/tests/GeoJsonTest.php b/tests/GeoJsonTest.php
index c4496e7..e0ccedc 100644
--- a/tests/GeoJsonTest.php
+++ b/tests/GeoJsonTest.php
@@ -48,7 +48,7 @@ public function testUnserializationWithBoundingBox($assoc): void
         $point = GeoJson::jsonUnserialize($json);
 
         $this->assertInstanceOf(Point::class, $point);
-        $this->assertSame('Point', $point->getType());
+        $this->assertSame(GeoJson::TYPE_POINT, $point->getType());
         $this->assertSame([1, 1], $point->getCoordinates());
 
         $boundingBox = $point->getBoundingBox();
@@ -80,7 +80,7 @@ public function testUnserializationWithCrs($assoc): void
         $point = GeoJson::jsonUnserialize($json);
 
         $this->assertInstanceOf(Point::class, $point);
-        $this->assertSame('Point', $point->getType());
+        $this->assertSame(GeoJson::TYPE_POINT, $point->getType());
         $this->assertSame([1, 1], $point->getCoordinates());
 
         $crs = $point->getCrs();
@@ -142,7 +142,7 @@ public function testUnserializationWithInvalidCoordinates($value): void
         $this->expectExceptionMessage('Point expected "coordinates" property of type array, ' . $valueType . ' given');
 
         GeoJson::jsonUnserialize([
-            'type' => 'Point',
+            'type' => GeoJson::TYPE_POINT,
             'coordinates' => $value,
         ]);
     }
@@ -153,7 +153,7 @@ public function testFeatureUnserializationWithInvalidGeometry(): void
         $this->expectExceptionMessage('Feature expected "geometry" property of type array or object, string given');
 
         GeoJson::jsonUnserialize([
-            'type' => 'Feature',
+            'type' => GeoJson::TYPE_FEATURE,
             'geometry' => 'must be array or object, but this is a string',
         ]);
     }
@@ -164,7 +164,7 @@ public function testFeatureUnserializationWithInvalidProperties(): void
         $this->expectExceptionMessage('Feature expected "properties" property of type array or object, string given');
 
         GeoJson::jsonUnserialize([
-            'type' => 'Feature',
+            'type' => GeoJson::TYPE_FEATURE,
             'properties' => 'must be array or object, but this is a string',
         ]);
     }
@@ -180,12 +180,12 @@ public function provideJsonDecodeAssocOptions()
     public function provideGeoJsonTypesWithCoordinates()
     {
         return [
-            'LineString' => ['LineString'],
-            'MultiLineString' => ['MultiLineString'],
-            'MultiPoint' => ['MultiPoint'],
-            'MultiPolygon' => ['MultiPolygon'],
-            'Point' => ['Point'],
-            'Polygon' => ['Polygon'],
+            GeoJson::TYPE_LINE_STRING => [GeoJson::TYPE_LINE_STRING],
+            GeoJson::TYPE_MULTI_LINE_STRING => [GeoJson::TYPE_MULTI_LINE_STRING],
+            GeoJson::TYPE_MULTI_POINT => [GeoJson::TYPE_MULTI_POINT],
+            GeoJson::TYPE_MULTI_POLYGON => [GeoJson::TYPE_MULTI_POLYGON],
+            GeoJson::TYPE_POINT => [GeoJson::TYPE_POINT],
+            GeoJson::TYPE_POLYGON => [GeoJson::TYPE_POLYGON],
         ];
     }
 
diff --git a/tests/Geometry/GeometryCollectionTest.php b/tests/Geometry/GeometryCollectionTest.php
index b888468..50418d0 100644
--- a/tests/Geometry/GeometryCollectionTest.php
+++ b/tests/Geometry/GeometryCollectionTest.php
@@ -90,11 +90,11 @@ public function testSerialization(): void
         $collection = new GeometryCollection($geometries);
 
         $expected = [
-            'type' => 'GeometryCollection',
+            'type' => GeoJson::TYPE_GEOMETRY_COLLECTION,
             'geometries' => [['geometry1'], ['geometry2']],
         ];
 
-        $this->assertSame('GeometryCollection', $collection->getType());
+        $this->assertSame(GeoJson::TYPE_GEOMETRY_COLLECTION, $collection->getType());
         $this->assertSame($geometries, $collection->getGeometries());
         $this->assertSame($expected, $collection->jsonSerialize());
     }
@@ -121,14 +121,14 @@ public function testUnserialization($assoc): void
         $collection = GeoJson::jsonUnserialize($json);
 
         $this->assertInstanceOf(GeometryCollection::class, $collection);
-        $this->assertSame('GeometryCollection', $collection->getType());
+        $this->assertSame(GeoJson::TYPE_GEOMETRY_COLLECTION, $collection->getType());
         $this->assertCount(1, $collection);
 
         $geometries = iterator_to_array($collection);
         $geometry = $geometries[0];
 
         $this->assertInstanceOf(Point::class, $geometry);
-        $this->assertSame('Point', $geometry->getType());
+        $this->assertSame(GeoJson::TYPE_POINT, $geometry->getType());
         $this->assertSame([1, 1], $geometry->getCoordinates());
     }
 
@@ -145,7 +145,7 @@ public function testUnserializationShouldRequireGeometriesProperty(): void
         $this->expectException(UnserializationException::class);
         $this->expectExceptionMessage('GeometryCollection expected "geometries" property of type array, none given');
 
-        GeoJson::jsonUnserialize(['type' => 'GeometryCollection']);
+        GeoJson::jsonUnserialize(['type' => GeoJson::TYPE_GEOMETRY_COLLECTION]);
     }
 
     public function testUnserializationShouldRequireGeometriesArray(): void
@@ -153,6 +153,6 @@ public function testUnserializationShouldRequireGeometriesArray(): void
         $this->expectException(UnserializationException::class);
         $this->expectExceptionMessage('GeometryCollection expected "geometries" property of type array');
 
-        GeoJson::jsonUnserialize(['type' => 'GeometryCollection', 'geometries' => null]);
+        GeoJson::jsonUnserialize(['type' => GeoJson::TYPE_GEOMETRY_COLLECTION, 'geometries' => null]);
     }
 }
diff --git a/tests/Geometry/LineStringTest.php b/tests/Geometry/LineStringTest.php
index 9fa051f..df20f46 100644
--- a/tests/Geometry/LineStringTest.php
+++ b/tests/Geometry/LineStringTest.php
@@ -42,11 +42,11 @@ public function testSerialization(): void
         $lineString = new LineString($coordinates);
 
         $expected = [
-            'type' => 'LineString',
+            'type' => GeoJson::TYPE_LINE_STRING,
             'coordinates' => $coordinates,
         ];
 
-        $this->assertSame('LineString', $lineString->getType());
+        $this->assertSame(GeoJson::TYPE_LINE_STRING, $lineString->getType());
         $this->assertSame($coordinates, $lineString->getCoordinates());
         $this->assertSame($expected, $lineString->jsonSerialize());
     }
@@ -73,7 +73,7 @@ public function testUnserialization($assoc): void
         $expectedCoordinates = [[1, 1], [2, 2]];
 
         $this->assertInstanceOf(LineString::class, $lineString);
-        $this->assertSame('LineString', $lineString->getType());
+        $this->assertSame(GeoJson::TYPE_LINE_STRING, $lineString->getType());
         $this->assertSame($expectedCoordinates, $lineString->getCoordinates());
     }
 
diff --git a/tests/Geometry/LinearRingTest.php b/tests/Geometry/LinearRingTest.php
index beac0cd..367f4b9 100644
--- a/tests/Geometry/LinearRingTest.php
+++ b/tests/Geometry/LinearRingTest.php
@@ -5,6 +5,7 @@
 namespace GeoJson\Tests\Geometry;
 
 use GeoJson\Exception\InvalidArgumentException;
+use GeoJson\GeoJson;
 use GeoJson\Geometry\LinearRing;
 use GeoJson\Geometry\LineString;
 use GeoJson\Geometry\Point;
@@ -71,11 +72,11 @@ public function testSerialization(): void
         $linearRing = new LinearRing($coordinates);
 
         $expected = [
-            'type' => 'LineString',
+            'type' => GeoJson::TYPE_LINE_STRING,
             'coordinates' => $coordinates,
         ];
 
-        $this->assertSame('LineString', $linearRing->getType());
+        $this->assertSame(GeoJson::TYPE_LINE_STRING, $linearRing->getType());
         $this->assertSame($coordinates, $linearRing->getCoordinates());
         $this->assertSame($expected, $linearRing->jsonSerialize());
     }
diff --git a/tests/Geometry/MultiLineStringTest.php b/tests/Geometry/MultiLineStringTest.php
index 78a3811..d4f1a1b 100644
--- a/tests/Geometry/MultiLineStringTest.php
+++ b/tests/Geometry/MultiLineStringTest.php
@@ -50,11 +50,11 @@ public function testSerialization(): void
         $multiLineString = new MultiLineString($coordinates);
 
         $expected = [
-            'type' => 'MultiLineString',
+            'type' => GeoJson::TYPE_MULTI_LINE_STRING,
             'coordinates' => $coordinates,
         ];
 
-        $this->assertSame('MultiLineString', $multiLineString->getType());
+        $this->assertSame(GeoJson::TYPE_MULTI_LINE_STRING, $multiLineString->getType());
         $this->assertSame($coordinates, $multiLineString->getCoordinates());
         $this->assertSame($expected, $multiLineString->jsonSerialize());
     }
@@ -84,7 +84,7 @@ public function testUnserialization($assoc): void
         ];
 
         $this->assertInstanceOf(MultiLineString::class, $multiLineString);
-        $this->assertSame('MultiLineString', $multiLineString->getType());
+        $this->assertSame(GeoJson::TYPE_MULTI_LINE_STRING, $multiLineString->getType());
         $this->assertSame($expectedCoordinates, $multiLineString->getCoordinates());
     }
 
diff --git a/tests/Geometry/MultiPointTest.php b/tests/Geometry/MultiPointTest.php
index d8fd376..30a5266 100644
--- a/tests/Geometry/MultiPointTest.php
+++ b/tests/Geometry/MultiPointTest.php
@@ -46,11 +46,11 @@ public function testSerialization(): void
         $multiPoint = new MultiPoint($coordinates);
 
         $expected = [
-            'type' => 'MultiPoint',
+            'type' => GeoJson::TYPE_MULTI_POINT,
             'coordinates' => $coordinates,
         ];
 
-        $this->assertSame('MultiPoint', $multiPoint->getType());
+        $this->assertSame(GeoJson::TYPE_MULTI_POINT, $multiPoint->getType());
         $this->assertSame($coordinates, $multiPoint->getCoordinates());
         $this->assertSame($expected, $multiPoint->jsonSerialize());
     }
@@ -77,7 +77,7 @@ public function testUnserialization($assoc): void
         $expectedCoordinates = [[1, 1], [2, 2]];
 
         $this->assertInstanceOf(MultiPoint::class, $multiPoint);
-        $this->assertSame('MultiPoint', $multiPoint->getType());
+        $this->assertSame(GeoJson::TYPE_MULTI_POINT, $multiPoint->getType());
         $this->assertSame($expectedCoordinates, $multiPoint->getCoordinates());
     }
 
diff --git a/tests/Geometry/MultiPolygonTest.php b/tests/Geometry/MultiPolygonTest.php
index 779abf4..58ad275 100644
--- a/tests/Geometry/MultiPolygonTest.php
+++ b/tests/Geometry/MultiPolygonTest.php
@@ -50,11 +50,11 @@ public function testSerialization(): void
         $multiPolygon = new MultiPolygon($coordinates);
 
         $expected = [
-            'type' => 'MultiPolygon',
+            'type' => GeoJson::TYPE_MULTI_POLYGON,
             'coordinates' => $coordinates,
         ];
 
-        $this->assertSame('MultiPolygon', $multiPolygon->getType());
+        $this->assertSame(GeoJson::TYPE_MULTI_POLYGON, $multiPolygon->getType());
         $this->assertSame($coordinates, $multiPolygon->getCoordinates());
         $this->assertSame($expected, $multiPolygon->jsonSerialize());
     }
@@ -84,7 +84,7 @@ public function testUnserialization($assoc): void
         ];
 
         $this->assertInstanceOf(MultiPolygon::class, $multiPolygon);
-        $this->assertSame('MultiPolygon', $multiPolygon->getType());
+        $this->assertSame(GeoJson::TYPE_MULTI_POLYGON, $multiPolygon->getType());
         $this->assertSame($expectedCoordinates, $multiPolygon->getCoordinates());
     }
 
diff --git a/tests/Geometry/PointTest.php b/tests/Geometry/PointTest.php
index fcbc562..a3acbe6 100644
--- a/tests/Geometry/PointTest.php
+++ b/tests/Geometry/PointTest.php
@@ -68,11 +68,11 @@ public function testSerialization(): void
         $point = new Point($coordinates);
 
         $expected = [
-            'type' => 'Point',
+            'type' => GeoJson::TYPE_POINT,
             'coordinates' => $coordinates,
         ];
 
-        $this->assertSame('Point', $point->getType());
+        $this->assertSame(GeoJson::TYPE_POINT, $point->getType());
         $this->assertSame($coordinates, $point->getCoordinates());
         $this->assertSame($expected, $point->jsonSerialize());
     }
@@ -94,7 +94,7 @@ public function testUnserialization($assoc): void
         $point = GeoJson::jsonUnserialize($json);
 
         $this->assertInstanceOf(Point::class, $point);
-        $this->assertSame('Point', $point->getType());
+        $this->assertSame(GeoJson::TYPE_POINT, $point->getType());
         $this->assertSame([1, 1], $point->getCoordinates());
     }
 
diff --git a/tests/Geometry/PolygonTest.php b/tests/Geometry/PolygonTest.php
index f30fba3..c71d393 100644
--- a/tests/Geometry/PolygonTest.php
+++ b/tests/Geometry/PolygonTest.php
@@ -56,11 +56,11 @@ public function testSerialization(): void
         $polygon = new Polygon($coordinates);
 
         $expected = [
-            'type' => 'Polygon',
+            'type' => GeoJson::TYPE_POLYGON,
             'coordinates' => $coordinates,
         ];
 
-        $this->assertSame('Polygon', $polygon->getType());
+        $this->assertSame(GeoJson::TYPE_POLYGON, $polygon->getType());
         $this->assertSame($coordinates, $polygon->getCoordinates());
         $this->assertSame($expected, $polygon->jsonSerialize());
     }
@@ -90,7 +90,7 @@ public function testUnserialization($assoc): void
         ];
 
         $this->assertInstanceOf(Polygon::class, $polygon);
-        $this->assertSame('Polygon', $polygon->getType());
+        $this->assertSame(GeoJson::TYPE_POLYGON, $polygon->getType());
         $this->assertSame($expectedCoordinates, $polygon->getCoordinates());
     }