Use proper to_meter conversion factor for OGC WKT GEOGCS

cerv8za · Oct 7, 2015 · 3379ad3 · 3379ad3
1 parent d03c1d1
commit 3379ad3
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Showing 2 changed files with 17 additions and 1 deletion.
diff --git a/lib/wkt.js b/lib/wkt.js
@@ -111,7 +111,13 @@ function cleanWKT(wkt) {
  wkt.units = 'meter';
  }
  if (wkt.UNIT.convert) {
- wkt.to_meter = parseFloat(wkt.UNIT.convert, 10);
+ if (wkt.type === 'GEOGCS') {
+ if (wkt.DATUM && wkt.DATUM.SPHEROID) {
+ wkt.to_meter = parseFloat(wkt.UNIT.convert, 10)*wkt.DATUM.SPHEROID.a;
+ }
+ } else {
+ wkt.to_meter = parseFloat(wkt.UNIT.convert, 10);
+ }
  }
  }
 

diff --git a/test/test.js b/test/test.js
@@ -171,6 +171,16 @@ function startTests(chai, proj4, testPoints) {
  assert.typeOf(proj4.defs['foo'], 'object');
  proj4.defs('urn:x-ogc:def:crs:EPSG:4326', proj4.defs('EPSG:4326'));
  assert.strictEqual(proj4.defs['urn:x-ogc:def:crs:EPSG:4326'], proj4.defs['EPSG:4326']);
+
+ describe('wkt', function() {
+ it('should provide the correct conversion factor for WKT GEOGCS projections', function() {
+ proj4.defs('EPSG:4269', 'GEOGCS["NAD83",DATUM["North_American_Datum_1983",SPHEROID["GRS 1980",6378137,298.257222101,AUTHORITY["EPSG","7019"]],AUTHORITY["EPSG","6269"]],PRIMEM["Greenwich",0,AUTHORITY["EPSG","8901"]],UNIT["degree",0.01745329251994328,AUTHORITY["EPSG","9122"]],AUTHORITY["EPSG","4269"]]');
+ assert.equal(proj4.defs['EPSG:4269'].to_meter, 6378137*0.01745329251994328);
+
+ proj4.defs('EPSG:4279', 'GEOGCS["OS(SN)80",DATUM["OS_SN_1980",SPHEROID["Airy 1830",6377563.396,299.3249646,AUTHORITY["EPSG","7001"]],AUTHORITY["EPSG","6279"]],PRIMEM["Greenwich",0,AUTHORITY["EPSG","8901"]],UNIT["degree",0.01745329251994328,AUTHORITY["EPSG","9122"]],AUTHORITY["EPSG","4279"]]');
+ assert.equal(proj4.defs['EPSG:4279'].to_meter, 6377563.396*0.01745329251994328);
+ }); 
+ });
  });
  describe('errors', function() {
  it('should throw an error for an unknown ref', function() {