For any recitified map in the Map Warper at http://warp.worldmap.harvartd.edu, once you are signed in, go to the export tab for the map you want to bring into WorldMap.
Right click on “Tiles base URL” and “copy link location”. Then you will just paste that into the right place in WorldMap. Here's how:
Once you have copied the Tile Base URL as described above, go to WorldMap http://worldmap.harvard.edu and open the Map you want to add the Warper layer to.
Once in your WorldMap map, click the "Add layers" link at the upper left.
Go to the "External Data" tab and click "add another server". Make sure “wms” toggle is selected.
Paste your URL here and make sure there are no spaces at the end.
Click "Add Server".
The name of the map layer from Warper that you want to add to WorldMap should show up. Click on it to highlight it.
Click "Add Layer" at the bottom of the form.
Close this Add Layers form.
You should see your layer loaded to your map at the bottom of the layer list to the left of the map.
If you can't see your new layer displayed it may be because another layer is displaying on top of it. Turn off the other layers or drag your new layer to be above the others.
If you still can't see it, right click on your new layer and select "Zoom to Layer Extent". This should take you to the layer.
If your backdrop is displayed it may be because you are now zoomed in too far for the Google Terrain base map to display. In that case try turning on Google Hybrid.
Then save your Map and you will be able to come back to it. Or click link and save a URL of the view that way if you don't have edit permission for the Map.