More information in admin field

[xlqian]

we have noticed that there is already an issue about the admin field: #7, which is partially interesting for us and our opinion is also shared in this very issue.

Another problem we met recently is that we'd like to expose more details in admin field especially coord and id.

final result will look like:

{
    …
    "admin": [
         {
              "type": "country",
              "name": "France",
              "admin_level": 1,
              "coord": "42;42"
         },
         {
              "type": "region",
              "name": "Nord-Pas-de-Calais",
              "admin_level": 2,
              "coord": "42;42"
         },
         {
              "type": "mycustomlevel",
              "name": "Nord",
              "admin_level": 3,
              "coord": "42;42"
         },
    ]
}