1 files changed, 134 insertions, 0 deletions
diff --git a/web/js/OpenLayers.Projection.CH1903Plus.js b/web/js/OpenLayers.Projection.CH1903Plus.js
new file mode 100644
index 000000000..6cb888bf5
--- /dev/null
+++ b/web/js/OpenLayers.Projection.CH1903Plus.js
@@ -0,0 +1,134 @@
+/**
+ * OpenLayers Swiss (CH1903+/LV95) grid projection transformations
+ * 
+ * Provides transform functions for WGS84<->CH1903+ projections.
+ *
+ * Maths courtesy of the Swiss Federal Office of Topography:
+ * http://www.swisstopo.admin.ch/internet/swisstopo/en/home/products/software/products/skripts.html
+ * Simplifed a bit, and with x/y swapped the normal way round.
+ */
+
+// Use the same calcs as CH1903 but with offset.
+// Maximum distortion is 3M which should be sufficient for our purposes.
+var LV95_X_OFFSET = 2000000;
+var LV95_Y_OFFSET = 1000000;
+
+
+OpenLayers.Projection.CH1903Plus = {
+
+    // Convert WGS lat/long (° dec) to CH x
+    WGStoCHx: function(lat, lng) {
+
+        // Converts degrees dec to seconds
+        lat = lat * 3600;
+        lng = lng * 3600;
+
+        // Auxiliary values (% Bern)
+        var lat_aux = (lat - 169028.66) / 10000;
+        var lng_aux = (lng - 26782.5) / 10000;
+
+        // Process X
+        var x = 600072.37 + LV95_X_OFFSET;
+        x = x + (211455.93 * lng_aux);
+        x = x - (10938.51 * lng_aux * lat_aux);
+        x = x - (0.36 * lng_aux * Math.pow(lat_aux, 2));
+        x = x - (44.54 * Math.pow(lng_aux, 3));
+
+        return x;
+    },
+
+    // Convert WGS lat/long (° dec) to CH y
+    WGStoCHy: function(lat, lng) {
+
+        // Converts degrees dec to seconds
+        lat = lat * 3600;
+        lng = lng * 3600;
+
+        // Auxiliary values (% Bern)
+        var lat_aux = (lat - 169028.66)/10000;
+        var lng_aux = (lng - 26782.5)/10000;
+
+        // Process Y
+        var y = 200147.07 + LV95_Y_OFFSET;
+        y = y + (308807.95 * lat_aux);
+        y = y + (3745.25 * Math.pow(lng_aux, 2));
+        y = y + (76.63 * Math.pow(lat_aux, 2));
+        y = y - (194.56 * Math.pow(lng_aux, 2) * lat_aux);
+        y = y + (119.79 * Math.pow(lat_aux, 3));
+
+        return y;
+      
+    },
+
+    // Convert CH x/y to WGS lat
+    chToWGSlat: function(x, y) {
+
+        // Converts militar to civil and  to unit = 1000km
+        // Axiliary values (% Bern)
+        var x_aux = (x - 600000 - LV95_X_OFFSET) / 1000000;
+        var y_aux = (y - 200000 - LV95_Y_OFFSET) / 1000000;
+
+        // Process lat
+        var lat = 16.9023892;
+        lat = lat + (3.238272 * y_aux);
+        lat = lat - (0.270978 * Math.pow(x_aux, 2));
+        lat = lat - (0.002528 * Math.pow(y_aux, 2));
+        lat = lat - (0.0447 * Math.pow(x_aux, 2) * y_aux);
+        lat = lat - (0.0140 * Math.pow(y_aux, 3));
+
+        // Unit 10000" to 1 " and converts seconds to degrees (dec)
+        lat = lat * 100 / 36;
+
+        return lat;
+
+    },
+
+    // Convert CH x/y to WGS long
+    chToWGSlng: function(x, y) {
+
+        // Converts militar to civil and  to unit = 1000km
+        // Axiliary values (% Bern)
+        var x_aux = (x - 600000 - LV95_X_OFFSET) / 1000000;
+        var y_aux = (y - 200000 - LV95_Y_OFFSET) / 1000000;
+
+        // Process long
+        var lng = 2.6779094;
+        lng = lng + (4.728982 * x_aux);
+        lng = lng + (0.791484 * x_aux * y_aux);
+        lng = lng + (0.1306 * x_aux * Math.pow(y_aux, 2));
+        lng = lng - (0.0436 * Math.pow(x_aux, 3));
+
+        // Unit 10000" to 1 " and converts seconds to degrees (dec)
+        lng = lng * 100 / 36;
+
+        return lng;
+
+    },
+
+    // Function to convert a WGS84 coordinate to a Swiss coordinate.
+    projectForwardSwiss: function(point) {
+        var x = OpenLayers.Projection.CH1903Plus.WGStoCHx(point.y, point.x),
+            y = OpenLayers.Projection.CH1903Plus.WGStoCHy(point.y, point.x);
+        point.x = x;
+        point.y = y;
+        return point;
+    },
+
+    // Function to convert a Swiss coordinate to a WGS84 coordinate. 
+    projectInverseSwiss: function(point) {
+        var lon = OpenLayers.Projection.CH1903Plus.chToWGSlng(point.x, point.y);
+        var lat = OpenLayers.Projection.CH1903Plus.chToWGSlat(point.x, point.y);
+        point.x = lon;
+        point.y = lat;
+        return point;
+    }
+};
+
+/**
+ * Note: One transform declared
+ * Transforms from EPSG:4326 to EPSG:2056
+ */
+ OpenLayers.Projection.addTransform("EPSG:4326", "EPSG:2056",
+    OpenLayers.Projection.CH1903Plus.projectForwardSwiss);
+ OpenLayers.Projection.addTransform("EPSG:2056", "EPSG:4326",
+    OpenLayers.Projection.CH1903Plus.projectInverseSwiss);