added lots of helper functions

src/stwkit.js

@@ -148,6 +148,64 @@ var STWkit = {
             parent = true;
         }
         return result;
+    },
+    convertDDtoDDM : function(dd, lat) {
+        var round = function (value, n) {
+            return Math.round(value * Math.pow(10, n)) / Math.pow(10, n);
+        };
+
+        var pad = function (n, width) {
+            var z = '0';
+            n = n + '';
+            return n.length >= width ? n : new Array(width - n.length + 1).join(z) + n;
+        };
+        var hemisphere;
+        if ((dd >= 0) && lat)
+            hemisphere = "N";
+        if ((dd < 0) && lat)
+            hemisphere = "S";
+        if ((dd >= 0) && !lat)
+            hemisphere = "E";
+        if ((dd < 0) && !lat)
+            hemisphere = "W";
+
+        var degree = parseInt((Math.abs(dd) + "").split(".")[0]);
+        var minutes = round(60.0 * (Math.abs(dd) - degree), 3);
+        var parts = minutes.toFixed(3).split('.');
+        return hemisphere + " " + pad(degree, 2) + " " + pad(parts[0], 2) + "." + pad(parts[1], 3);
+    },
+    featurecollection: function() {
+        var json = {};
+        json["type"] = "FeatureCollection";
+        json["features"] = [];
+        return json;
+    },
+    createFeature: function(type) {
+        var feature = {};
+        feature["type"] = "Feature";
+        feature["properties"] = {};
+        feature["geometry"] = {};
+        feature["geometry"]["type"] = type;
+        feature["geometry"]["coordinates"] = [];
+        return feature;
+    },
+    uriencodejson: function(json) {
+        var query = "";
+        for (var key in json) {
+            query += encodeURIComponent(key) + "=" + encodeURIComponent(json[key]) + "&";
+        }
+        return query;
+    },
+
+    intersect: function(a, b) {
+        return (a.left <= b.right &&
+            b.left <= a.right &&
+            a.top <= b.bottom &&
+            b.top <= a.bottom);
+    },
+
+    getRectangle: function(p) {
+        return { left: p.x, right: p.x + 210, top: p.y, bottom: p.y + 20 };
     }
 
 };
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