Javascript 如何使用OpenLayer显示多段线
使用下面的代码,我得到了我想要的结果,也就是说,我得到了给定纬度、经度上的多段线Javascript 如何使用OpenLayer显示多段线,javascript,html,openlayers,Javascript,Html,Openlayers,使用下面的代码,我得到了我想要的结果,也就是说,我得到了给定纬度、经度上的多段线 <html> <head> <title>OpenLayers Example</title> <script src="http://openlayers.org/api/OpenLayers.js"></script> </head> <body>
<html>
<head>
<title>OpenLayers Example</title>
<script src="http://openlayers.org/api/OpenLayers.js"></script>
</head>
<body>
<div style="width:100%; height:100%" id="map"></div>
<script defer="defer" type="text/javascript">
var map = new OpenLayers.Map('map');
var wms = new OpenLayers.Layer.WMS( "OpenLayers WMS",
"http://vmap0.tiles.osgeo.org/wms/vmap0", {layers: 'basic'} );
var start_point = new OpenLayers.Geometry.Point(0,10);
var start_point_1= new OpenLayers.Geometry.Point(0,15);
var start_point_2= new OpenLayers.Geometry.Point(5,20);
var end_point = new OpenLayers.Geometry.Point(30,0);
var end_point_1 = new OpenLayers.Geometry.Point(40,0);
var myTrip =[start_point, start_point_1, start_point_2 , end_point, end_point_1];
var vector = new OpenLayers.Layer.Vector();
vector.addFeatures([new OpenLayers.Feature.Vector(new OpenLayers.Geometry.LineString(myTrip ))]);
map.addLayers([vector]);
map.addLayers([wms]);
map.zoomToMaxExtent();
</script>
</body>
</html>
OpenLayers示例
var map=newopenlayers.map('map');
var wms=new OpenLayers.Layer.wms(“OpenLayers wms”,
"http://vmap0.tiles.osgeo.org/wms/vmap0“,{层:'基本'});
var start_point=新的OpenLayers.Geometry.point(0,10);
var start_point_1=新的OpenLayers.Geometry.point(0,15);
var start_point_2=新的OpenLayers.Geometry.point(5,20);
var end_point=新OpenLayers.Geometry.point(30,0);
var end_point_1=新的OpenLayers.Geometry.point(40,0);
var myTrip=[start_point,start_point_1,start_point_2,end_point,end_point_1];
var vector=新的OpenLayers.Layer.vector();
addFeatures([new OpenLayers.Feature.vector(new OpenLayers.Geometry.LineString(myTrip)));
map.addLayers([vector]);
map.addLayers([wms]);
zoomToMaxExtent();
输出
但当我使用谷歌地图时,它不起作用,也就是说,它只是向我展示简单的地图
<html>
<head>
<title>OpenLayers Example</title>
<script src="http://openlayers.org/api/OpenLayers.js"></script>
<script src="http://maps.google.com/maps/api/js?v=3.2&sensor=false"></script>
</head>
<body>
<div style="width:100%; height:100%" id="map"></div>
<script defer="defer" type="text/javascript">
var map = new OpenLayers.Map('map');
var wms = new OpenLayers.Layer.Google(
"Google Streets", // the default
{numZoomLevels: 20}
);
var lonlat = new OpenLayers.LonLat(73.589,19.54).transform(
new OpenLayers.Projection("EPSG:4326"), // transform from WGS 1984
new OpenLayers.Projection("EPSG:900913") // to Spherical Mercator
);
var zoom = 7;
var start_point = new OpenLayers.Geometry.Point(0,10);
var start_point_1= new OpenLayers.Geometry.Point(0,15);
var start_point_2= new OpenLayers.Geometry.Point(5,20);
var end_point = new OpenLayers.Geometry.Point(30,0);
var end_point_1 = new OpenLayers.Geometry.Point(40,0);
var myTrip =[start_point, start_point_1, start_point_2 , end_point, end_point_1];
var vector = new OpenLayers.Layer.Vector();
vector.addFeatures([new OpenLayers.Feature.Vector(new OpenLayers.Geometry.LineString(myTrip ))]);
map.addLayers([vector]);
map.addLayer(wms);
map.zoomToMaxExtent();
map.setCenter(lonlat, zoom);
</script>
</body>
</html>
OpenLayers示例
var map=newopenlayers.map('map');
var wms=new OpenLayers.Layer.Google(
“Google Streets”,//默认值
{numZoomLevels:20}
);
var lonlat=新OpenLayers.lonlat(73.589,19.54).转换(
新OpenLayers.Projection(“EPSG:4326”),//从WGS 1984转换而来
新OpenLayers.Projection(“EPSG:900913”)//到球形墨卡托
);
var=7;
var start_point=新的OpenLayers.Geometry.point(0,10);
var start_point_1=新的OpenLayers.Geometry.point(0,15);
var start_point_2=新的OpenLayers.Geometry.point(5,20);
var end_point=新OpenLayers.Geometry.point(30,0);
var end_point_1=新的OpenLayers.Geometry.point(40,0);
var myTrip=[start_point,start_point_1,start_point_2,end_point,end_point_1];
var vector=新的OpenLayers.Layer.vector();
addFeatures([new OpenLayers.Feature.vector(new OpenLayers.Geometry.LineString(myTrip)));
map.addLayers([vector]);
地图添加层(wms);
zoomToMaxExtent();
地图设置中心(lonlat,zoom);
输出
为什么这不起作用,我怎样才能使它起作用。如果直接使用Google Map API而不是openlayer,我可以得到所需的结果。Google Map使用墨卡托(EPSG:900913)坐标,但您的几何体在未投影的地理坐标中(EPSG:4326)。因此,这条线将是赤道上非常小的点
您应该将其转换为Mercator(使用lonlat变量也可以完成相同的操作):
请注意,此字符串将放置在非洲,但您的地图将缩放到印度。要看到这条线,您必须从初始视图中缩小地图
var myTrip =[start_point, start_point_1, start_point_2 , end_point, end_point_1];
var vector = new OpenLayers.Layer.Vector();
var geom = new OpenLayers.Geometry.LineString(myTrip);
geom = geom.transform(
new OpenLayers.Projection("EPSG:4326"),
new OpenLayers.Projection("EPSG:900913")
);
vector.addFeatures([new OpenLayers.Feature.Vector(geom)]);
map.addLayers([vector]);