I have a published WMS service that supports EPSG:27700 (projection of the map document) and EPSG:4326. I want to leave these as supported projections but also include EPSG:3857.
I've been reading online: Defining a custom projection for a WMS service—Documentation (10.3 and 10.3.1) | ArcGIS for Server
about defining custom projections, but the example isn't described very well and after trying a few things I'm left rather confused.
I get the impression I can Edit the WMS service via Admin by adding the listCustomCRS property, however I don't know what value(s) to set to add EPSG:3857. The example on the page says it "overwrites the definition of EPSG:3857 using another WKT string", but I don't want to overwrite it, I want to add it. I've tried adding the property: "listCustomCRS": "EPSG:3857=DEFAULT", but this doesn't work, it could be because "DEFAULT" needs setting to something else, but how do I find out what?
So can anyone please give me the answer, how do I add EPSG:3857 as an additionally supported projection to a WMS service which is already supporting EPSG:27700 and EPSG:4326 (without changing the projection of the source map document, this is 27700)?