Center and Scale with Multiple Layers

POST http://<hostname>:<port>/rest/Spatial/MappingService/maps/image.png;w=400;h=400;c=8,42,epsg%3A4269;s=8500000
Content-type: application/json
Authorization: <Basic or Spectrum Token>

{
   "layers":[
      {
         "type":"NamedLayer",
         "name":"/Samples/NamedLayers/WorldcapFeatureLayer"
      },
      {
         "type":"NamedLayer",
         "name":"/Samples/NamedLayers/UK_REGNS_Layer"
      },
      {
         "type":"NamedLayer",
         "name":"/Samples/NamedLayers/WorldFeatureLayer"
      }
   ]
}