Changeset 2188

Timestamp:

01/30/07 04:16:30 (2 years ago)

Author:

bwoodall

Message:

Added a new switch (newTile) to _initTiles to test out a way to make
consistant tile requests ( mainly lat) while using GoogleMaps

Added some functions to go along with the switch

To use the new switch use something like;

var tmplay = new OpenLayers.Layer.WMS("OL WMS", "http://somewhere/wms",

{layers: 'basicCoolStuff'},
{newTile: 1} );

Files:

• sandbox/bwoodall/openlayers/lib/OpenLayers/Layer/Grid.js (modified) (4 diffs)

sandbox/bwoodall/openlayers/lib/OpenLayers/Layer/Grid.js

@@ -23 +23 @@
-    /** @type Integer */
-    buffer: 2,
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+    /** @type Integer */
+    newTile: 0,
-
-    /**
@@ -108 +111 @@
-                this._initTiles();
-            } else {
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-                while (true) {
-                    var tlLayer = this.grid[0][0].position;
@@ -163 +167 @@
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-    /**
+     * Routines to convert back and forth from lon/lat to Integer
+     * representation of tiles 
+     */
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+    /**
+     * @private
+     *
+     * @param {float} lon
+     * @param {Integer} tilesAtThisZoom
+     *
+     * @returns A integer representing the lon at a particular Zoom
+     * @type Integer
+     */
+    _lon2Gx:function(lon,tilesAtThisZoom) {
+        var x = Math.floor((180+lon) * tilesAtThisZoom / 360);
+        return x;
+    },
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+    /**
+     * @private
+     * @param {float} lat
+     * @param {Integer} tilesAtThisZoom
+     *
+     * @returns A integer representing the lat at a particular Zoom
+     * @type Integer
+     */
+    _lat2Gy:function(lat,tilesAtThisZoom) {
+        var srlat = Math.sin( lat * Math.PI / 180);
+        var y = Math.floor(((1 - (0.5 * Math.log((1 + srlat) / (1 - srlat))) / Math.PI) / 2.0) * tilesAtThisZoom);
+        return y;
+    },
+
+    /**
+     * @private
+     * @param {Integer} x
+     * @param {Integer} tilesAtThisZoom
+     *
+     * @returns A float (lon) representing the integer tile at a particular Zoom
+     * @type float
+     */
+    _Gx2lon:function(x, tilesAtThisZoom) {
+        var lonWidth = 360.0 / tilesAtThisZoom;
+        var lon = -180 + (x * lonWidth);
+        return lon;
+    },
+
+    /**
+     * @private
+     * @param {Integer} y
+     * @param {Integer} tilesAtThisZoom
+     *
+     * @returns A float (lat) representing the integer tile at a particular Zoom
+     * @type float
+     */
+    _Gy2lat:function(y, tilesAtThisZoom) {
+        var latHeight = 2.0 / tilesAtThisZoom;
+        var lat = ((tilesAtThisZoom / 2 - y - 1) * latHeight);
+        latHeight += lat;
+        latHeight = (2.0 * Math.atan(Math.exp(Math.PI * latHeight)))
+                 - (Math.PI/2);
+        latHeight *= (180/Math.PI);
+        lat = (2.0 * Math.atan(Math.exp(Math.PI * lat))) - (Math.PI/2);
+        lat *= (180/Math.PI);
+        latHeight -= lat;
+        if (latHeight < 0.0) {
+                lat = lat + latHeight;
+                latHeight = -latHeight;
+        }
+        return lat;
+    },
+
+    /**
-     * @private
-     */
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-        var extent = this.map.getMaxExtent();
-        var resolution = this.map.getResolution();
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-        //now actually draw the tiles
-        this.spiralTileLoad();