ArcGIS REST server projection with OpenLayers

Question

I'm adding an ArcGIS tile server to my openlayers tile server options via this javascript API. I have it displaying the map correctly, but it seems stretched out horizontally (I have a feeling the default projection may be causing this).

The URL I'm pointing it to is:

http://services.arcgisonline.com/ArcGIS/rest/services/World_Street_Map/MapServer/export

And declaring the layer like so:

var layer = new OpenLayers.Layer.ArcGIS93Rest(null, 
        'http://services.arcgisonline.com/ArcGIS/rest/services/World_Street_Map
         /MapServer/export',
        { layers:"0,1,2" } );

Does anyone know the projection I should be using? The API says I can specify a projection by adding an srs Projection ID property alongside my layers option, but I'm not sure even what the possible values are.

Answer 1

You do not need to define any srs to your ArcGIS93Rest layer if your map projection and service projection is identical.

    var options = {
        projection: new OpenLayers.Projection("EPSG:900913"),
        displayProjection: new OpenLayers.Projection("EPSG:4326"),
        units: "m",
    };

the below code working is working as it should work.

 arcRest= new OpenLayers.Layer.ArcGIS93Rest( "ArcGIS Server Layer",
                'http://services.arcgisonline.com/ArcGIS/rest/services/World_Street_Map
                 /MapServer/export', 
                {layers: "show:0,2",
                 TRANSPARENT: true},
                {isBaseLayer: false,
                 extractAttributes: true});


                 
  map.addLayer(arcRest);

Answer 2

So no matter what I tried and the different projections I used, the map would still appear stretched out.

I did, however, find a little hacky solution using the tile server at http://services.arcgisonline.com/ArcGIS/rest/services/World_Street_Map/MapServer/tile. This works out very well. By translating the OSM url parameters, I leveraged the OSM layer API in OpenLayers to work for the ArcGIS server.

Here's the code:

var tileServiceURL = "http://services.arcgisonline.com/ArcGIS/rest/services/World_Street_Map/MapServer/tile/${z}/${y}/${x}";

layer = new OpenLayers.Layer.OSM(null, tileServiceURL, {
    transitionEffect: 'resize',
    wrapDateLine: false
});

For now this suits my needs perfectly.

Answer 3

you can get to that information right on the rest endpoint.
http://services.arcgisonline.com/ArcGIS/rest/services/World_Street_Map/MapServer