{
 "layers": [
  {
   "layerId": 0,
   "layerName": "Hillingdon Mask",
   "layerType": "Feature Layer",
   "minScale": 0,
   "maxScale": 0,
   "legend": [
    {
     "label": "",
     "url": "62bd1f44734664c4ef3a397087a6fa32",
     "imageData": "iVBORw0KGgoAAAANSUhEUgAAABQAAAAUCAYAAACNiR0NAAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAOElEQVQ4je3VoREAQAwCwQj6JnT+8zIaXHIFrD1I6gpFslHhcKAdfGJ2oB8CxuhAPywEScYW8MUHXJkGTv0D0IAAAAAASUVORK5CYII=",
     "contentType": "image/png",
     "groupId": "0",
     "height": 20,
     "width": 20
    }
   ],
   "legendGroups": [
    {
     "id": "0",
     "heading": ""
    }
   ]
  }
 ]
}