Kill jsts

index.js

@@ -1,5 +1,4 @@
-// depend on jsts for now https://github.com/bjornharrtell/jsts/blob/master/examples/overlay.html
-var jsts = require('jsts');
+var gh = require('gh-clipping-algorithm');
 
 /**
  * Takes two {@link Polygon|polygons} and finds their intersection. If they share a border, returns the border; if they don't intersect, returns undefined.
@@ -58,25 +57,32 @@ var jsts = require('jsts');
  * //=intersection
  */
 module.exports = function(poly1, poly2) {
-  var geom1, geom2;
-  if(poly1.type === 'Feature') geom1 = poly1.geometry;
-  else geom1 = poly1;
-  if(poly2.type === 'Feature') geom2 = poly2.geometry;
-  else geom2 = poly2;
-  var reader = new jsts.io.GeoJSONReader();
-  var a = reader.read(JSON.stringify(geom1));
-  var b = reader.read(JSON.stringify(geom2));
-  var intersection = a.intersection(b);
-  var parser = new jsts.io.GeoJSONParser();
+  var a = poly1.coordinates ? poly1.coordinates : poly1.geometry.coordinates;
+  var b = poly2.coordinates ? poly2.coordinates : poly2.geometry.coordinates;
+  var u = gh.intersect(a, b);
 
-  intersection = parser.write(intersection);
-  if(intersection.type === 'GeometryCollection' && intersection.geometries.length === 0) {
+  var feature = {
+    "type": "Feature",
+    "properties": {},
+    "geometry": {}
+  };
+
+  if (!u || u.length == 0) {
     return undefined;
-  } else {
-    return {
-      type: 'Feature',
-      properties: {},
-      geometry: intersection
-    };
   }
+
+  if (gh.utils.isMultiPolygon(u)) {
+    if (u.length > 1) {
+      feature.geometry.type = "MultiPolygon";
+      feature.geometry.coordinates = u;
+    } else {
+      feature.geometry.type = "Polygon";
+      feature.geometry.coordinates = u[0];
+    }
+  } else if (gh.utils.isPolygon(u)) {
+    feature.geometry.type = "Polygon";
+    feature.geometry.coordinates = u;
+  }
+
+  return feature;
 };

package.json

@@ -27,9 +27,10 @@
     "glob": "~4.3.5",
     "tape": "~3.5.0",
     "dox": "^0.6.1",
-    "doxme": "^1.4.3"
+    "doxme": "^1.4.3",
+    "geojson-equality": "^0.1.4"
   },
   "dependencies": {
-    "jsts": "~0.15.0"
+    "gh-clipping-algorithm": "^0.*"
   }
 }

test/fixtures/out/Intersect1.json

@@ -1 +1 @@
-{"type":"Feature","properties":{},"geometry":{"type":"Polygon","coordinates":[[[-79.94623496447946,32.89900638172028],[-79.88571166992188,32.887659962078956],[-79.89395141601562,32.75551989829049],[-79.92322780260464,32.73910022106017],[-79.93789672851562,32.74108223150125],[-79.93034362792969,32.76475877693074],[-79.97360229492188,32.76071688548088],[-79.97428894042969,32.83690450361482],[-79.94623496447946,32.89900638172028]]]}}
+{"type":"Feature","properties":{},"geometry":{"type":"Polygon","coordinates":[[[-79.92322780260464,32.73910022106017],[-79.89395141601562,32.75551989829049],[-79.88571166992188,32.887659962078956],[-79.94623496447946,32.89900638172028],[-79.97428894042969,32.83690450361482],[-79.97360229492188,32.76071688548088],[-79.93034362792969,32.76475877693074],[-79.93789672851562,32.74108223150125],[-79.92322780260464,32.73910022106017]]]}}

test/fixtures/out/armenia.json

@@ -1 +1 @@
-{"type":"Feature","properties":{},"geometry":{"type":"Polygon","coordinates":[[[43.582746,41.092143],[44.97248,41.248129],[45.179496,40.985354],[45.560351,40.81229],[45.359175,40.561504],[45.891907,40.218476],[45.610012,39.899994],[46.034534,39.628021],[46.483499,39.464155],[46.50572,38.770605],[46.143623,38.741201],[45.735379,39.319719],[45.739978,39.473999],[45.298145,39.471751],[45.001987,39.740004],[44.79399,39.713003],[44.400009,40.005],[43.656436,40.253564],[43.752658,40.740201],[43.582746,41.092143]]]}}
+{"type":"Feature","properties":{},"geometry":{"type":"Polygon","coordinates":[[[43.582746,41.092143],[44.97248,41.248129],[45.179496,40.985354],[45.560351,40.81229],[45.359175,40.561504],[45.891907,40.218476],[45.610012,39.899994],[46.034534,39.628021],[46.483499,39.464155],[46.50572,38.770605],[46.143623,38.741201],[45.735379,39.319719],[45.739978,39.473999],[45.298145,39.471751],[45.001987,39.740004],[44.79399,39.713003],[44.400009,40.005],[43.656436,40.253564],[43.752658,40.740201],[43.582746,41.092143]]]}}

test/test.js

@@ -1,16 +1,17 @@
 var intersect = require('../'),
   test = require('tape'),
   glob = require('glob'),
-  fs = require('fs');
+  fs = require('fs')
+  equal = new(require('geojson-equality'));
 
-var REGEN = true;
+var REGEN = false;
 
 test('intersect -- features', function(t){
   glob.sync(__dirname + '/fixtures/in/*.json').forEach(function(input) {
       var features = JSON.parse(fs.readFileSync(input));
       var output = intersect(features[0], features[1]);
       if (REGEN) fs.writeFileSync(input.replace('/in/', '/out/'), JSON.stringify(output));
-      t.deepEqual(output, JSON.parse(fs.readFileSync(input.replace('/in/', '/out/'))), input);
+      t.ok(equal.compare(output, JSON.parse(fs.readFileSync(input.replace('/in/', '/out/')))), input);
   });
   t.end();
 });
@@ -20,7 +21,7 @@ test('intersect -- geometries', function(t){
       var features = JSON.parse(fs.readFileSync(input));
       var output = intersect(features[0].geometry, features[1].geometry);
       if (REGEN) fs.writeFileSync(input.replace('/in/', '/out/'), JSON.stringify(output));
-      t.deepEqual(output, JSON.parse(fs.readFileSync(input.replace('/in/', '/out/'))), input);
+      t.ok(equal.compare(output, JSON.parse(fs.readFileSync(input.replace('/in/', '/out/')))), input);
   });
   t.end();
 });
@@ -30,4 +31,4 @@ test('intersect -- no overlap', function(t){
   var output = intersect(noOverlap[0].geometry, noOverlap[1].geometry);
   t.deepEqual(output, undefined);
   t.end();
-});
+});