@turf/difference - npm Package Compare versions

Comparing version 4.2.1 to 4.2.2

index.d.ts

 /// <reference types="geojson" />
 
-type Polygon = GeoJSON.Feature<GeoJSON.Polygon>;
-type MultiPolygon = GeoJSON.Feature<GeoJSON.MultiPolygon>;
+import {Polygon, MultiPolygon, Feature} from '@turf/meta'
 
+type Input = Feature<Polygon|MultiPolygon> | Polygon | MultiPolygon;
+type Output = Feature<Polygon|MultiPolygon> | undefined;
+
 /**
  * http://turfjs.org/docs/#difference
  */
-declare function difference(poly1: Polygon, poly2: Polygon): Polygon|MultiPolygon;
+declare function difference(polygon1: Input, polygon2: Input): Output;
 declare namespace difference { }
 export = difference;

index.js

 // depend on jsts for now https://github.com/bjornharrtell/jsts/blob/master/examples/overlay.html
 var jsts = require('jsts');
+var area = require('@turf/area');
+var feature = require('@turf/helpers').feature;
+var getGeom = require('@turf/invariant').getGeom;
+var flattenEach = require('@turf/meta').flattenEach;
 
 /**
- * Finds the difference between two {@link Polygon|polygons} by clipping the second
- * polygon from the first.
+ * Finds the difference between two {@link Polygon|polygons} by clipping the second polygon from the first.
  *
  * @name difference
- * @param {Feature<Polygon>} p1 input Polygon feature
- * @param {Feature<Polygon>} p2 Polygon feature to difference from `p1`
- * @return {Feature<(Polygon|MultiPolygon)>} a Polygon or MultiPolygon feature showing the area of `p1` excluding the area of `p2`
+ * @param {Feature<Polygon|MultiPolygon>} polygon1 input Polygon feature
+ * @param {Feature<Polygon|MultiPolygon>} polygon2 Polygon feature to difference from polygon1
+ * @returns {Feature<Polygon|MultiPolygon>|undefined} a Polygon or MultiPolygon feature showing the area of `polygon1` excluding the area of `polygon2` (if empty returns `undefined`)
  * @example
- * var poly1 = {
+ * var polygon1 = {
  *   "type": "Feature",
- *   "properties": {},
+ *   "properties": {
+ *     "fill": "#F00",
+ *     "fill-opacity": 0.1
+ *   },
  *   "geometry": {
@@ -27,61 +33,60 @@ *     "type": "Polygon",
  * };
- * var poly2 = {
+ * var polygon2 = {
  *   "type": "Feature",
- *   "properties": {},
+ *   "properties": {
+ *     "fill": "#00F",
+ *     "fill-opacity": 0.1
+ *   },
  *   "geometry": {
  *     "type": "Polygon",
- *     "coordinates": [[
- *       [-46.650009, -23.631314],
- *       [-46.650009, -23.5237],
- *       [-46.509246, -23.5237],
- *       [-46.509246, -23.631314],
- *       [-46.650009, -23.631314]
- *     ]]
+ *     "coordinates": [[[126, -28], [140, -28], [140, -20], [126, -20], [126, -28]]]
  *   }
  * };
  *
- * var difference = turf.difference(poly1, poly2);
+ * var difference = turf.difference(polygon1, polygon2);
  *
  * //addToMap
- * poly1.properties.fill = '#0f0';
- * poly2.properties.fill = '#00f';
- * difference.properties.fill = '#f00';
- * var addToMap = [poly1, poly2, difference];
+ * var addToMap = [polygon1, polygon2, difference];
  */
+module.exports = function (polygon1, polygon2) {
+    var geom1 = getGeom(polygon1);
+    var geom2 = getGeom(polygon2);
+    var properties = polygon1.properties || {};
 
-module.exports = function (p1, p2) {
-    var poly1 = JSON.parse(JSON.stringify(p1));
-    var poly2 = JSON.parse(JSON.stringify(p2));
-    if (poly1.type !== 'Feature') {
-        poly1 = {
-            type: 'Feature',
-            properties: {},
-            geometry: poly1
-        };
-    }
-    if (poly2.type !== 'Feature') {
-        poly2 = {
-            type: 'Feature',
-            properties: {},
-            geometry: poly2
-        };
-    }
+    // Issue #721 - JSTS can't handle empty polygons
+    geom1 = removeEmptyPolygon(geom1);
+    geom2 = removeEmptyPolygon(geom2);
+    if (!geom1) return undefined;
+    if (!geom2) return feature(geom1, properties);
 
+    // JSTS difference operation
     var reader = new jsts.io.GeoJSONReader();
-    var a = reader.read(JSON.stringify(poly1.geometry));
-    var b = reader.read(JSON.stringify(poly2.geometry));
+    var a = reader.read(geom1);
+    var b = reader.read(geom2);
     var differenced = a.difference(b);
-
     if (differenced.isEmpty()) return undefined;
-
     var writer = new jsts.io.GeoJSONWriter();
-    var geojsonGeometry = writer.write(differenced);
+    var geom = writer.write(differenced);
 
-    poly1.geometry = differenced;
+    return feature(geom, properties);
+};
 
-    return {
-        type: 'Feature',
-        properties: poly1.properties,
-        geometry: geojsonGeometry
-    };
-};
+/**
+ * Detect Empty Polygon
+ *
+ * @param {Geometry<Polygon|MultiPolygon>} geom Geometry Object
+ * @returns {Geometry<Polygon|MultiPolygon>|undefined} removed any polygons with no areas
+ */
+function removeEmptyPolygon(geom) {
+    switch (geom.type) {
+    case 'Polygon':
+        if (area(geom) > 1) return geom;
+        return undefined;
+    case 'MultiPolygon':
+        var coordinates = [];
+        flattenEach(geom, function (feature) {
+            if (area(feature) > 1) coordinates.push(feature.geometry.coordinates);
+        });
+        if (coordinates.length) return {type: 'MultiPolygon', coordinates: coordinates};
+    }
+}

package.json

 {
   "name": "@turf/difference",
-  "version": "4.2.1",
+  "version": "4.2.2",
   "description": "turf difference module",
@@ -30,10 +30,15 @@ "main": "index.js",
   "devDependencies": {
-    "benchmark": "^1.0.0",
+    "benchmark": "^2.1.4",
     "glob": "~5.0.5",
-    "tape": "~4.0.0"
+    "load-json-file": "^2.0.0",
+    "tape": "^4.6.3",
+    "write-json-file": "^2.0.0"
   },
   "dependencies": {
-    "jsts": "1.3.0",
-    "@turf/helpers": "^4.2.0"
+    "@turf/area": "^4.2.0",
+    "@turf/helpers": "^4.2.0",
+    "@turf/invariant": "^4.2.0",
+    "@turf/meta": "^4.2.0",
+    "jsts": "^1.4.0"
   }
 }

README.md

@@ -5,9 +5,8 @@ # @turf/difference
 
-Finds the difference between two [polygons](http://geojson.org/geojson-spec.html#polygon) by clipping the second
-polygon from the first.
+Finds the difference between two [polygons](http://geojson.org/geojson-spec.html#polygon) by clipping the second polygon from the first.
 
 **Parameters**
 
--   `p1` **[Feature](http://geojson.org/geojson-spec.html#feature-objects)<[Polygon](http://geojson.org/geojson-spec.html#polygon)>** input Polygon feature
--   `p2` **[Feature](http://geojson.org/geojson-spec.html#feature-objects)<[Polygon](http://geojson.org/geojson-spec.html#polygon)>** Polygon feature to difference from `p1`
+-   `polygon1` **[Feature](http://geojson.org/geojson-spec.html#feature-objects)<([Polygon](http://geojson.org/geojson-spec.html#polygon) \| [MultiPolygon](http://geojson.org/geojson-spec.html#multipolygon))>** input Polygon feature
+-   `polygon2` **[Feature](http://geojson.org/geojson-spec.html#feature-objects)<([Polygon](http://geojson.org/geojson-spec.html#polygon) \| [MultiPolygon](http://geojson.org/geojson-spec.html#multipolygon))>** Polygon feature to difference from polygon1
 
@@ -17,5 +16,8 @@ **Examples**
 ```javascript
-var poly1 = {
+var polygon1 = {
   "type": "Feature",
-  "properties": {},
+  "properties": {
+    "fill": "#F00",
+    "fill-opacity": 0.1
+  },
   "geometry": {
@@ -32,28 +34,32 @@ "type": "Polygon",
 };
-var poly2 = {
+var polygon2 = {
   "type": "Feature",
-  "properties": {},
+  "properties": {
+    "fill": "#00F",
+    "fill-opacity": 0.1
+  },
   "geometry": {
     "type": "Polygon",
-    "coordinates": [[
-      [-46.650009, -23.631314],
-      [-46.650009, -23.5237],
-      [-46.509246, -23.5237],
-      [-46.509246, -23.631314],
-      [-46.650009, -23.631314]
-    ]]
+    "coordinates": [[[126, -28], [140, -28], [140, -20], [126, -20], [126, -28]]]
   }
 };
 
-var difference = turf.difference(poly1, poly2);
+var difference = turf.difference(polygon1, polygon2);
 
 //addToMap
-poly1.properties.fill = '#0f0';
-poly2.properties.fill = '#00f';
-difference.properties.fill = '#f00';
-var addToMap = [poly1, poly2, difference];
+var addToMap = [polygon1, polygon2, difference];
 ```
 
-Returns **[Feature](http://geojson.org/geojson-spec.html#feature-objects)<([Polygon](http://geojson.org/geojson-spec.html#polygon) \| [MultiPolygon](http://geojson.org/geojson-spec.html#multipolygon))>** a Polygon or MultiPolygon feature showing the area of `p1` excluding the area of `p2`
+Returns **([Feature](http://geojson.org/geojson-spec.html#feature-objects)<([Polygon](http://geojson.org/geojson-spec.html#polygon) \| [MultiPolygon](http://geojson.org/geojson-spec.html#multipolygon))> | [undefined](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/undefined))** a Polygon or MultiPolygon feature showing the area of `polygon1` excluding the area of `polygon2` (if empty returns `undefined`)
 
+# removeEmptyPolygon
+
+Detect Empty Polygon
+
+**Parameters**
+
+-   `geom` **[Geometry](http://geojson.org/geojson-spec.html#geometry)<([Polygon](http://geojson.org/geojson-spec.html#polygon) \| [MultiPolygon](http://geojson.org/geojson-spec.html#multipolygon))>** Geometry Object
+
+Returns **([Geometry](http://geojson.org/geojson-spec.html#geometry)<([Polygon](http://geojson.org/geojson-spec.html#polygon) \| [MultiPolygon](http://geojson.org/geojson-spec.html#multipolygon))> | [undefined](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/undefined))** removed any polygons with no areas
+
 <!-- This file is automatically generated. Please don't edit it directly:
@@ -60,0 +66,0 @@ if you find an error, edit the source file (likely index.js), and re-run

No alert changes

Improved metrics

Total package byte prevSize

8463

increased by24.51%

Lines of code

96

increased by9.09%

Number of lines in readme file

86

increased by7.5%

Worsened metrics

Dependency count

5

increased by150%

Dev dependency count

5

increased by66.67%

Dependency changes

• + Added@turf/area@^4.2.0

• + Added@turf/invariant@^4.2.0

• + Added@turf/meta@^4.2.0

• + Added@mapbox/geojson-area@0.2.2(transitive)

• + Added@turf/area@4.7.3(transitive)

• + Added@turf/invariant@4.7.3(transitive)

• + Added@turf/meta@4.7.4(transitive)

• + Addedjsts@1.6.2(transitive)

• + Addedwgs84@0.0.0(transitive)

• - Removedjsts@1.3.0(transitive)

• Updatedjsts@^1.4.0