I have been using map.setBaseLayer(layer); to switch to my preferred map layer, using the localStorage variable layer that is stored in my web browser, upon initialization of the map. But I realize that this is creating unnecessary calls to load the default (first layer) map tiles that I may not need if the preferred layer is the second or third one. Is there a way that I can pre-select the base layer to be displayed (before map initialization), without changing the order of the map layers?
[GIS] How to set the base layer of map before initialization
layersopenlayers-2
Related Solutions
Take a look at this code example:
var adresspt_wfs = new OpenLayers.Layer.Vector("Address points WFS", {
strategies: [new OpenLayers.Strategy.BBOX(), saveStrategy],
protocol: new OpenLayers.Protocol.WFS({
url: "http://localhost:8080/geoserver/wfs",
featurePrefix: "XXXX" //<-- GeoServer workspace name
featureType: "RAILWAY",//<-- layer name
featureNS: "http://localhost:8080/MIA", //<-- Edit Workspace Namespace URI
srsName: "EPSG:900913",
geometryName: "SDO_GEOMETRY" //<-- geometry field
})
});
The featureNS property is equivalent to your Namespace URI in the Edit Workspace page of GeoServer:
I am currently building an application in which the user draws lines and shapes on a map. I am using the browser's LocalStorage to save the vector data in GeoJSON format (see here). It's a concise, legible format. I retrieve the vector data using these 2 functions:
function getFeatures(){
var ret=new Array();
for(i in vectors.features){
if(vectors.features[i].geometry.getVertices().length>1){ //excludes points
ret.push(serialize(vectors.features[i]));
}
}
return ret;
}
function serialize(feature) {
var out_options = {
'internalProjection': map.baseLayer.projection,
'externalProjection': new OpenLayers.Projection("EPSG:4326")
};
var type = "geojson";
var pretty = false;
var str = new OpenLayers.Format.GeoJSON(out_options).write(feature, pretty);
return(str);
}
I also built a server-side script which returns the user's drawing as a file, and allows a user to upload that file which then gets saved back to LocalStorage. Does that help at all?
Best Answer
map.baseLayer = your-layerOpenLayers add the first baselayer in map.baseLayer property but calls it only when add to map. So you can change the layer before being called.