5
注意：我知道還有另一個類似於這個問題，但它沒有得到回答，我需要知道如何處理混合投影與GeoJSON和OSM。Openlayers投影與OSM樣式的地圖和GeoJSON矢量圖層
我很困惑。我在Android上使用OSMDroid API進行映射，並希望使用OpenLayers和GeoExt進行復制，但我在包含GeoJSON節點和動作事件時遇到了投影問題。
我的圖集是基於OSM的，並且駐留在與此HTML/JS相同的Web服務器上。在下面看到它。我意識到我的界限不起作用，我的預測可能完全錯誤。我一直在測試不同的組合。
問題是我的地圖顯示正確並居中良好。但是：
我的GeoJSON功能節點離開地圖。他們處於不同的投影長/緯度，但我不知道如何設置或將GeoJSON long/lat轉換爲當前的地圖投影。
我的mapCtrl不起作用。當我點擊它lonlat是另一個投影（OSM的投影COORDS），我似乎無法將它們轉換）
的程度/界限是如何工作的將是任何提示，不勝感激
有人可以請一些投影建議幫忙嗎？嘆息......我對此沒有耐心。
這裏是我的全JS，如：
var mapPanel, store, gridPanel, mainPanel, nodePop, mapPop;
Ext.onReady(function() {
var map, mapLayer, vecLayer;
var lon = -70.885610;
var lat = 38.345822;
var zoom = 17;
var maxZoom = 18;
var toProjection = new OpenLayers.Projection("EPSG:4326");
var fromProjection = new OpenLayers.Projection("EPSG:900913");
var extent = new OpenLayers.Bounds(-1.32,51.71,-1.18,51.80).transform(fromProjection, toProjection);
// Setup the node layer feature store and push it all into a vector layer
vecLayer = new OpenLayers.Layer.Vector("vector");
store = new GeoExt.data.FeatureStore({
layer: vecLayer,
fields: [
{name: 'name', type: 'string'},
{name: 'status', type: 'string'}
],
proxy: new GeoExt.data.ProtocolProxy({
protocol: new OpenLayers.Protocol.HTTP({
url: "data/sa.json",
format: new OpenLayers.Format.GeoJSON()
})
}),
autoLoad: true
});
// Setup the basic map layer using OSM style tile retreival to pull tiles
// from the same server hosting this service
map = new OpenLayers.Map(
'map', {
controls:[
new OpenLayers.Control.Navigation(),
new OpenLayers.Control.PanZoomBar(),
new OpenLayers.Control.Attribution(),
new OpenLayers.Control.ScaleLine()],
projection: toProjection,
displayProjection: fromProjection,
numZoomLevels: 20,
fractionalZoom: true
});
mapLayer = new OpenLayers.Layer.OSM(
"Local Tiles",
"tiles/${z}/${x}/${y}.png",
{
zoomOffset: 17,
resolutions: [1.194328566741945,0.5971642833709725,0.2985821416854863] // Zoom level 17 - 19
});
map.addLayers([mapLayer, vecLayer]);
// Create a map panel
mapPanel = new GeoExt.MapPanel({
title: "Map",
region: "center",
map: map,
xtype: "gx_mappanel",
center: new OpenLayers.LonLat(lon, lat),
zoom: zoom
});
// Create a grid panel for listing nodes
gridPanel = new Ext.grid.GridPanel({
title: "Nodes",
region: "east",
store: store,
width: 275,
columns: [{
header: "Name",
width: 200,
dataIndex: "name"
}, {
header: "Status",
width: 75,
dataIndex: "status"
}],
sm: new GeoExt.grid.FeatureSelectionModel({
autoPanMapOnSelection: true
})
});
// Create the main view port
new Ext.Viewport({
layout: "border",
items: [{
region: "north",
contentEl: "title",
height: 150
}, mapPanel, gridPanel]
});
var lonLat = new OpenLayers.LonLat(lon, lat).transform(new OpenLayers.Projection("EPSG:4326"), map.getProjectionObject());
map.setCenter(lonLat, zoom);
// Attach all the event driven stuff here...
// Create a node selection pop up control
function nodeAction(feature) {
nodePop = new GeoExt.Popup({
title: 'Node selected',
location: feature,
width: 200,
html: "",
maximizable: true,
collapsible: true
});
nodePop.on({
close: function() {
if(OpenLayers.Util.indexOf(vectorLayer.selectedFeatures, this.feature) > -1) {
selectCtrl.unselect(this.feature);
}
}
});
nodePop.show();
};
// Attach the pop to node/feature selection events
var selectCtrl = new OpenLayers.Control.SelectFeature(vecLayer);
vecLayer.events.on({
featureselected: function(e) {
nodeAction(e.feature);
}
});
// Create map selection pop up control
function mapAction(lonlat) {
mapPop = new GeoExt.Popup({
title: 'Map selected',
location: lonlat,
width: 200,
html: "You clicked on (" + lonlat.lon.toFixed(2) + ", " + lonlat.lat.toFixed(2) + ")",
maximizable: true,
collapsible: true,
map: mapPanel.map,
anchored: true
});
mapPop.doLayout();
mapPop.show();
};
var mapCtrl = new OpenLayers.Control.Click({
trigger: function(evt) {
var lonlat = mapPanel.map.getLonLatFromViewPortPx(evt.xy);
lonlat.transform(new OpenLayers.Projection("EPSG:4326"), mapPanel.map.getProjectionObject());
//.transform(new OpenLayers.Projection("EPSG:4326"), map.getProjectionObject());
mapAction(lonlat);
}
});
mapPanel.map.addControl(mapCtrl);
mapCtrl.activate();
});
// A control to handle user clicks on the map
OpenLayers.Control.Click = OpenLayers.Class(
OpenLayers.Control, {
defaultHandlerOptions: {
single: true,
double: false,
pixelTolerance: 0,
stopSingle: true
},
initialize: function(options) {
this.handlerOptions = OpenLayers.Util.extend(
options && options.handlerOptions || {},
this.defaultHandlerOptions
);
OpenLayers.Control.prototype.initialize.apply(
this, arguments
);
this.handler = new OpenLayers.Handler.Click(
this,
{ click: this.trigger },
this.handlerOptions
);
},
CLASS_NAME: "OpenLayers.Control.Click"
}
);
這裏的GeoJSON的我使用：
{
"type": "FeatureCollection",
"features": [
{
"geometry": {
"type": "Point",
"coordinates": [
-70.3856,
38.3458
]
},
"type": "Feature",
"properties": {
"name": "Node0",
"status": "Active",
"externalGraphic": "img/node2.png",
"graphicHeight": 75, "graphicWidth": 75
},
"id": 100
},
{
"geometry": {
"type": "Point",
"coordinates": [
-70.885810,
38.344722
]
},
"type": "Feature",
"properties": {
"name": "Node1",
"status": "Active",
"externalGraphic": "img/node2.png",
"graphicHeight": 75, "graphicWidth": 75
},
"id": 101
}
]
}