da07d0df2f
git-svn-id: http://svn.openlayers.org/trunk/openlayers@8447 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf
185 lines
7.0 KiB
HTML
185 lines
7.0 KiB
HTML
<html xmlns="http://www.w3.org/1999/xhtml">
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<head>
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<link rel="stylesheet" href="../theme/default/style.css" type="text/css" />
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<link rel="stylesheet" href="style.css" type="text/css" />
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<style type="text/css">
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#controlToggle li {
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list-style: none;
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}
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p {
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width: 512px;
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}
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#options {
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position: relative;
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width: 512px;
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}
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#output {
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float: right;
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}
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</style>
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<script src="../lib/OpenLayers.js"></script>
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<script type="text/javascript">
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var map, measureControls;
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OpenLayers.Util.onImageLoadErrorColor = "transparent";
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function init(){
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map = new OpenLayers.Map('map');
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var wmsLayer = new OpenLayers.Layer.WMS( "OpenLayers WMS",
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"http://labs.metacarta.com/wms/vmap0?", {layers: 'basic'});
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map.addLayers([wmsLayer]);
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map.addControl(new OpenLayers.Control.LayerSwitcher());
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map.addControl(new OpenLayers.Control.MousePosition());
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// style the sketch fancy
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var sketchSymbolizers = {
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"Point": {
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pointRadius: 4,
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graphicName: "square",
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fillColor: "white",
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fillOpacity: 1,
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strokeWidth: 1,
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strokeOpacity: 1,
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strokeColor: "#333333"
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},
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"Line": {
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strokeWidth: 3,
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strokeOpacity: 1,
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strokeColor: "#666666",
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strokeDashstyle: "dash"
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},
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"Polygon": {
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strokeWidth: 2,
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strokeOpacity: 1,
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strokeColor: "#666666",
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fillColor: "white",
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fillOpacity: 0.3
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}
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};
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var style = new OpenLayers.Style();
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style.addRules([
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new OpenLayers.Rule({symbolizer: sketchSymbolizers})
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]);
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var styleMap = new OpenLayers.StyleMap({"default": style});
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var options = {
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handlerOptions: {
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style: "default", // this forces default render intent
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layerOptions: {styleMap: styleMap},
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persist: true
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}
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};
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measureControls = {
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line: new OpenLayers.Control.Measure(
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OpenLayers.Handler.Path, options
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),
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polygon: new OpenLayers.Control.Measure(
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OpenLayers.Handler.Polygon, options
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)
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};
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var control;
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for(var key in measureControls) {
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control = measureControls[key];
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control.events.on({
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"measure": handleMeasurements,
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"measurepartial": handleMeasurements
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});
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map.addControl(control);
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}
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map.setCenter(new OpenLayers.LonLat(0, 0), 3);
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document.getElementById('noneToggle').checked = true;
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}
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function calcVincenty(geometry) {
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/**
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* Note: this function assumes geographic coordinates and
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* will fail otherwise. OpenLayers.Util.distVincenty takes
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* two objects representing points with geographic coordinates
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* and returns the geodesic distance between them (shortest
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* distance between the two points on an ellipsoid) in *kilometers*.
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*
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* It is important to realize that the segments drawn on the map
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* are *not* geodesics (or "great circle" segments). This means
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* that in general, the measure returned by this function
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* will not represent the length of segments drawn on the map.
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*/
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var dist = 0;
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for (var i = 1; i < geometry.components.length; i++) {
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var first = geometry.components[i-1];
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var second = geometry.components[i];
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dist += OpenLayers.Util.distVincenty(
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{lon: first.x, lat: first.y},
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{lon: second.x, lat: second.y}
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);
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}
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return dist;
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}
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function handleMeasurements(event) {
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var geometry = event.geometry;
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var units = event.units;
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var order = event.order;
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var measure = event.measure;
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var element = document.getElementById('output');
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var out = "";
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if(order == 1) {
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out += "measure: " + measure.toFixed(3) + " " + units;
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if (map.getProjection() == "EPSG:4326") {
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out += "<br /> Great Circle Distance: " +
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calcVincenty(geometry).toFixed(3) + " km *";
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}
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} else {
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out += "measure: " + measure.toFixed(3) + " " + units + "<sup>2</" + "sup>";
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}
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element.innerHTML = out;
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}
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function toggleControl(element) {
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for(key in measureControls) {
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var control = measureControls[key];
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if(element.value == key && element.checked) {
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control.activate();
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} else {
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control.deactivate();
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}
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}
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}
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</script>
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</head>
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<body onload="init()">
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<h1 id="title">OpenLayers Measure Example</h1>
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<p id="shortdesc">
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Demonstrates the measure control to measure distances and areas.
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</p>
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<div id="map" class="smallmap"></div>
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<div id="options">
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<div id="output">
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</div>
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<ul id="controlToggle">
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<li>
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<input type="radio" name="type" value="none" id="noneToggle"
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onclick="toggleControl(this);" checked="checked" />
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<label for="noneToggle">navigate</label>
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</li>
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<li>
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<input type="radio" name="type" value="line" id="lineToggle" onclick="toggleControl(this);" />
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<label for="lineToggle">measure distance</label>
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</li>
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<li>
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<input type="radio" name="type" value="polygon" id="polygonToggle" onclick="toggleControl(this);" />
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<label for="polygonToggle">measure area</label>
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</li>
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</ul>
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<p>* Note that the geometries drawn are planar geometries and the
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metrics returned by the measure control are planar measures. The
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"great circle" distance does not necessarily represent the length
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of the segments drawn on the map. Instead, it is a geodesic metric that
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represents the cumulative shortest path between all vertices in the
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geometry were they projected onto a sphere.</p>
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</div>
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</body>
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</html>
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