天津政府應急系統之GIS一張圖（arcgis api for flex）解說（三）顯示地圖坐標系模塊
config.xml文件的配置例如以下：
| 1 2 |
<widget
left="3" bottom="3"
config="widgets/Coordinate/CoordinateWidget.xml" url="widgets/Coordinate/CoordinateWidget.swf" />
|
源碼文件夾例如以下：
地圖坐標系模塊的源碼原理解析，具體的代碼在下載的開源flexviewer自帶的：
（1）CoordinateWidget.xml
1 <?xml version="1.0" ?>
2 <configuration label="Coordinates (default)"> 3 <!-- geo, dms, mercator 主要是坐標輸出單位。默認的是經緯度 --> 4 <outputunit>geo</outputunit> 5 </configuration>
(2)CoordinateWidget.mxml
1 <?xml version="1.0" encoding="utf-8"?> 19 <viewer:BaseWidget xmlns:fx="http://ns.adobe.com/mxml/2009"20 xmlns:s="library://ns.adobe.com/flex/spark" 21 xmlns:mx="library://ns.adobe.com/flex/mx" 22 xmlns:viewer="com.esri.viewer.*" 23 layout="horizontal" 24 widgetConfigLoaded="basewidget_widgetConfigLoadedHandler(event)"> 25 <fx:Script> 26 <![CDATA[ 27 import com.esri.ags.events.MapEvent; 28 import com.esri.ags.geometry.MapPoint; 29 import com.esri.ags.utils.WebMercatorUtil; 30 31 import mx.formatters.NumberBaseRoundType; 32 import mx.utils.StringUtil; 33 34 private var m_template:String; 35 private var m_func:Function = substitute; 36 37 protected function basewidget_widgetConfigLoadedHandler(event:Event):void 38 { 39 if (configXML) 40 { //以下是讀取CoordinateWidget.xml配置文件的資源。要是配置了的話 41 const decimalSeparator:String = configXML.numberformatter.@decimalseparator; 42 numberFormatter.decimalSeparatorTo = decimalSeparator ? decimalSeparator : "."; 43 const thousandsSeparator:String = configXML.numberformatter.@thousandsseparator; 44 numberFormatter.thousandsSeparatorTo = thousandsSeparator ?thousandsSeparator : ","; 45 numberFormatter.useThousandsSeparator = configXML.numberformatter.@usethousandsseparator == "true"; 46 numberFormatter.precision = parseFloat(configXML.numberformatter.@precision || "-1"); 47 const rounding:String = configXML.numberformatter.@rounding; 48 numberFormatter.rounding = rounding ? rounding : NumberBaseRoundType.NONE; 49 //獲取設置坐標顯示的字體和顏色樣式等 50 const color:String = configXML.labelstyle.@color[0] || configXML.label.@color[0]; 51 coords.setStyle("color", toNumber(color ? color : "0x000000")); 52 const fontFamily:String = configXML.labelstyle.@fontfamily[0] || configXML.label.@fontfamily[0]; 53 coords.setStyle("fontFamily", fontFamily ? fontFamily : "Verdana"); 54 const fontSize:String = configXML.labelstyle.@fontsize[0] || configXML.label.@fontsize[0]; 55 coords.setStyle("fontSize", parseInt(fontSize ?
fontSize : "9")); 56 const fontWeight:String = configXML.labelstyle.@fontweight[0] || configXML.label.@fontweight[0]; 57 coords.setStyle("fontWeight", fontWeight ?
fontWeight : "bold"); 58 59 // If no template specified, show them with a space in between (except for special case below) 60 m_template = configXML.labels.template[0] || configXML.label.@template[0] || "{0} {1}"; 61 62 if (map.loaded) 63 { 64 map_loadHandler(null); 65 } 66 else 67 { 68 map.addEventListener(MapEvent.LOAD, map_loadHandler);//載入地圖 69 } 70 } 71 72 function map_loadHandler(event:MapEvent):void 73 { 74 map.removeEventListener(MapEvent.LOAD, map_loadHandler); 75 const wkid:int = map.spatialReference.wkid; //獲取地圖的空間坐標參考系 76 m_func = substitute; 77 const outputUnit:String = configXML.outputunit;//獲取地圖的坐標顯示單位，從配置文件獲取 78 if (outputUnit === "mercator")//推斷地圖的坐標體系。墨卡托情況下運行 79 { 80 if (wkid === 4326 || wkid === 4269 || wkid === 4267) 81 { 82 m_func = geographicToMercator;//調用地理坐標系轉換墨卡托坐標系 83 } 84 } 85 else if (outputUnit === "geo")//地理坐標系情況下運行 86 { 87 if (wkid === 102100 || wkid === 102113 || wkid === 3857) 88 { 89 m_func = mercatorToGeographic;//調用墨卡托坐標系轉換地理坐標系 90 // special default for geographic outputs 91 m_template = configXML.labels.template[0] || configXML.label.@template[0] || getDefaultString("latitudeLabel") + ":{1} " + getDefaultString("longitudeLabel") + ":{0}";//設置坐標顯示的文字，比方經度，緯度 92 numberFormatter.precision = parseFloat(configXML.numberformatter.@precision || "6");//設置坐標顯示的位數 93 } 94 else if (wkid === 4326 || wkid === 4269 || wkid === 4267) 95 { 96 // special default for geographic outputs 97 m_template = configXML.labels.template[0] || configXML.label.@template[0] || getDefaultString("latitudeLabel") + ":{1} " + getDefaultString("longitudeLabel") + ":{0}"; 98 numberFormatter.precision = parseFloat(configXML.numberformatter.@precision || "6"); 99 } 100 } 101 else if (outputUnit === "dms")//經緯度顯示單位為度分秒形式情況下運行 102 { 103 if (wkid === 102100 || wkid === 102113 || wkid === 3857) 104 { 105 m_func = mercatorToDMS; 106 } 107 else if (wkid === 4326 || wkid === 4269 || wkid === 4267) 108 { 109 m_func = geographicToDMS; 110 } 111 } 112 map.addEventListener(MouseEvent.MOUSE_MOVE, map_mouseMoveHandler);//監聽地圖鼠標移動事件，用來獲取地圖經緯度的 113 } 114 } 115 116 private function toNumber(value:String):int//轉換單位計算 117 { 118 if (value.substr(0, 2) == "0x") 119 { 120 return parseInt(value, 16); 121 } 122 return parseInt(value, 10); 123 } 124 125 private function mercatorToGeographic(web:MapPoint):String//墨卡托轉換地理坐標系的函數 126 { 127 const geo:MapPoint = WebMercatorUtil.webMercatorToGeographic(web) as MapPoint;//arcgis api封裝好的轉換函數 128 return StringUtil.substitute(m_template, 129 numberFormatter.format(geo.x), 130 numberFormatter.format(geo.y)); 131 } 132 133 private function mercatorToDMS(web:MapPoint):String//墨卡托轉換經緯度度分秒形式的函數 134 { 135 const geo:MapPoint = WebMercatorUtil.webMercatorToGeographic(web) as MapPoint; 136 return StringUtil.substitute(m_template, DegToDMS.format(geo.x, DegToDMS.LON), DegToDMS.format(geo.y, DegToDMS.LAT)); 137 } 138 139 private function geographicToMercator(geo:MapPoint):String//地理坐標系轉換墨卡托的函數 140 { 141 const web:MapPoint = WebMercatorUtil.geographicToWebMercator(geo) as MapPoint; 142 return StringUtil.substitute(m_template, 143 numberFormatter.format(web.x), 144 numberFormatter.format(web.y)); 145 } 146 147 private function substitute(mapPoint:MapPoint):String 148 { 149 return StringUtil.substitute(m_template, 150 numberFormatter.format(mapPoint.x), 151 numberFormatter.format(mapPoint.y)); 152 } 153 154 private function geographicToDMS(mapPoint:MapPoint):String 155 { 156 const x:String = DegToDMS.format(mapPoint.x, DegToDMS.LON); 157 const y:String = DegToDMS.format(mapPoint.y, DegToDMS.LAT); 158 return StringUtil.substitute(m_template, x, y); 159 } 160 161 private function map_mouseMoveHandler(event:MouseEvent):void 162 { 163 const mapPoint:MapPoint = map.toMapFromStage(event.stageX, event.stageY);//獲取鼠標移動的地圖經緯度 164 coords.text = m_func(mapPoint); 165 } 166 ]]> 167 </fx:Script> 168 169 <fx:Declarations> 170 <mx:NumberFormatter id="numberFormatter"/> 171 </fx:Declarations> 172 <viewer:filters> 173 <mx:GlowFilter alpha="1" 174 blurX="3" 175 blurY="3" 176 color="0xFFFFFF" 177 strength="7"/> 178 </viewer:filters> 179 <s:Label id="coords" color="0x000000"/>//顯示經緯度的位置。顯示label 180 </viewer:BaseWidget>
（3）DegToDMS.as
1 package widgets.Coordinate 2 { 3 4 /** 5 * Utility class to pretty print decimal degree numbers. 6 * @private 7 */ 8 public final class DegToDMS 9 { 10 // Constants to define the format. 11 public static const LAT:String = "lat"; 12 13 public static const LON:String = "lon"; 14 15 /** 16 * Utility function to format a decimal degree number into a pretty string with degrees, minutes and seconds. 17 * @param decDeg the decimal degree number. 18 * @param decDir "lat" for a latitude number, "lon" for a longitude value. 19 * @return A pretty print string with degrees, minutes and seconds. 20 */ 21 public static function format(decDeg:Number, decDir:String):String//這個函數主要是用來把經緯度轉換度分秒的形式來展示經緯度，比方113度23分23秒等等 22 { 23 var d:Number = Math.abs(decDeg); 24 var deg:Number = Math.floor(d); 25 d = d - deg; 26 var min:Number = Math.floor(d * 60); 27 var av:Number = d - min / 60; 28 var sec:Number = Math.floor(av * 60 * 60); 29 if (sec == 60) 30 { 31 min++; 32 sec = 0; 33 } 34 if (min == 60) 35 { 36 deg++; 37 min = 0; 38 } 39 var smin:String = min < 10 ? "0" + min + "‘ " : min + "‘ "; 40 var ssec:String = sec < 10 ?"0" + sec + "\" " : sec + "\" "; 41 var sdir:String = (decDir == LAT) ? (decDeg < 0 ? "S" : "N") : (decDeg < 0 ?
"W" : "E"); 42 return deg + "\xB0 " + smin + ssec + sdir; 43 } 44 } 45 46 }
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天津政府應急系統之GIS一張圖（arcgis api for flex）解說（三）顯示地圖坐標系模塊