• OpenLayers测量距离和面积


    <!DOCTYPE html>
    <html>
      <head>
        <title>测量距离和面积</title>
        <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
        <meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=0">
        <meta name="apple-mobile-web-app-capable" content="yes">
        <link rel="stylesheet" href="./OpenLayers-2.12/theme/default/style.css" type="text/css" />
        <link rel="stylesheet" href="./css/style.css" type="text/css">
        <style type="text/css">
            #controlToggle li {
                list-style: none;
            }
            p {
                width: 512px;
            }
            #options {
                position: relative;
                width: 512px;
            }
            #output {
                float: right;
            }
            /* avoid pink tiles */
            .olImageLoadError {
                background-color: transparent !important;
            }
        </style>
        <script src="./OpenLayers-2.12/lib/OpenLayers.js"></script>
        <script type="text/javascript">
            var map, measureControls;
            function init(){
                map = new OpenLayers.Map('map');     
                var wmsLayer = new OpenLayers.Layer.WMS( "OpenLayers WMS", 
                    "http://vmap0.tiles.osgeo.org/wms/vmap0?", {layers: 'basic'}); 
                map.addLayers([wmsLayer]);
                map.addControl(new OpenLayers.Control.LayerSwitcher());
                map.addControl(new OpenLayers.Control.MousePosition());     
                // style the sketch fancy
                var sketchSymbolizers = {
                    "Point": {
                        pointRadius: 4,
                        graphicName: "square",
                        fillColor: "white",
                        fillOpacity: 1,
                        strokeWidth: 1,
                        strokeOpacity: 1,
                        strokeColor: "#333333"
                    },
                    "Line": {
                        strokeWidth: 3,
                        strokeOpacity: 1,
                        strokeColor: "#666666",
                        strokeDashstyle: "dash"
                    },
                    "Polygon": {
                        strokeWidth: 2,
                        strokeOpacity: 1,
                        strokeColor: "#666666",
                        fillColor: "white",
                        fillOpacity: 0.3
                    }
                };
                var style = new OpenLayers.Style();
                style.addRules([
                    new OpenLayers.Rule({symbolizer: sketchSymbolizers})
                ]);
                var styleMap = new OpenLayers.StyleMap({"default": style});
                
                // allow testing of specific renderers via "?renderer=Canvas", etc
                var renderer = OpenLayers.Util.getParameters(window.location.href).renderer;
                renderer = (renderer) ? [renderer] : OpenLayers.Layer.Vector.prototype.renderers;
    
                measureControls = {
                    line: new OpenLayers.Control.Measure(
                        OpenLayers.Handler.Path, {
                            persist: true,
                            handlerOptions: {
                                layerOptions: {
                                    renderers: renderer,
                                    styleMap: styleMap
                                }
                            }
                        }
                    ),
                    polygon: new OpenLayers.Control.Measure(
                        OpenLayers.Handler.Polygon, {
                            persist: true,
                            handlerOptions: {
                                layerOptions: {
                                    renderers: renderer,
                                    styleMap: styleMap
                                }
                            }
                        }
                    )
                };
                
                var control;
                for(var key in measureControls) {
                    control = measureControls[key];
                    control.events.on({
                        "measure": handleMeasurements,
                        "measurepartial": handleMeasurements
                    });
                    map.addControl(control);
                }
                
                map.setCenter(new OpenLayers.LonLat(0, 0), 3);
                
                document.getElementById('noneToggle').checked = true;
            }
            
            function handleMeasurements(event) {
                var geometry = event.geometry;
                var units = event.units;
                var order = event.order;
                var measure = event.measure;
                var element = document.getElementById('output');
                var out = "";
                if(order == 1) {
                    out += "测量距离: " + measure.toFixed(3) + " " + units;
                } else {
                    out += "测量面积: " + measure.toFixed(3) + " " + units + "<sup>2</" + "sup>";
                }
                element.innerHTML = out;
            }
    
            function toggleControl(element) {
                for(key in measureControls) {
                    var control = measureControls[key];
                    if(element.value == key && element.checked) {
                        control.activate();
                    } else {
                        control.deactivate();
                    }
                }
            }
            
        </script>
      </head>
      <body onload="init()">
        <div id="map" class="smallmap"></div>
        <div id="options">
            <div id="output">
            </div>
            <ul id="controlToggle">
                <li>
                    <input type="radio" name="type" value="none" id="noneToggle" onclick="toggleControl(this);" checked="checked" />
                    <label for="noneToggle">导航</label>
                </li>
                <li>
                    <input type="radio" name="type" value="line" id="lineToggle" onclick="toggleControl(this);" />
                    <label for="lineToggle">测量距离</label>
                </li>
                <li>
                    <input type="radio" name="type" value="polygon" id="polygonToggle" onclick="toggleControl(this);" />
                    <label for="polygonToggle">测量面积</label>
                </li>
            </ul>
        </div>
      </body>
    </html>
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  • 原文地址:https://www.cnblogs.com/Jeely/p/11175702.html
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