research new mappings file format

Would it be better to change the mappings.yaml file structure

FROM:

roads:
  - name: road 1
    ...
  - name: road 2
    ...

points:
  - name: points 1
    ...
  - name: points 2
    ...

areas:
  - name: area 1
    ...
  - name: area 2
    ...

TO:

- name: road 1
  type: LineString
  ...
- name: road 2
  type: LineString
  ...
- name: points 1
  type: MultiPoint
  ...
- name: points 2
  type: MultiPoint
  ...
- name: area 1
  type: Polygon
  ...
- name: area 2
  type: Polygon
  ...

???

Need to think about impacts (e.g., render order), and what (if any) code improvements could be made.