# Vector tiles
OS MasterMap Sites Layer is supplied as a national vector tiles set in a single MBTiles file. This is a lightweight set of tiles that are efficient and fast to render in your software, and which provide high resolution data and give a seamless experience when zooming in and out. The data is supplied in Web Mercator projection (ESPG:3857).
## Vector tiles schema
The vector tiles schema is detailed in the following table. In the zoom levels columns within the table, the letter *N* indicates that the specified layer and attribute are not mapped within that zoom level, whereas the letter *Y* indicates that the specified later and attribute are mapped within that zoom level.
### **Functional Site**
| Attribute | Zoom level: 0 to 11 | 12 | 13 | 14 | 15 |
|---|
| toid | N | Y | Y | Y | Y |
| polygon | N | Y | Y | Y | Y |
| function_status | N | Y | Y | Y | Y |
| function_theme | N | Y | Y | Y | Y |
| function | N | Y | Y | Y | Y |
| perimeter | N | Y | Y | Y | Y |
| Area | N | Y | Y | Y | Y |
| distinctive_name_1 | N | Y | Y | Y | Y |
| distinctive_name_2 | N | Y | Y | Y | Y |
| primary_addressbase_uprn | N | Y | Y | Y | Y |
| stakeholder_1 | N | Y | Y | Y | Y |
| stakeholder_1_role | N | Y | Y | Y | Y |
### **Access Point**
| Attribute | Zoom level: 0 to 11 | 12 | 13 | 14 | 15 |
|---|
| Toid | N | Y | Y | Y | Y |
| Point | N | Y | Y | Y | Y |
| ref_to_functional_site | N | Y | Y | Y | Y |
| access_type | N | Y | Y | Y | Y |
| access_mechanism | N | Y | Y | Y | Y |
| access_direction | N | Y | Y | Y | Y |
| access_use_restriction | N | Y | Y | Y | Y |
| ref_to_routing_point | N | Y | Y | Y | Y |
| ref_to_itn_road_node | N | Y | Y | Y | Y |
| height_qualifier | N | Y | Y | Y | Y |
| width_qualifier | N | Y | Y | Y | Y |
| weight_qualifier | N | Y | Y | Y | Y |
| length_qualifier | N | Y | Y | Y | Y |
| nature_of_access | N | Y | Y | Y | Y |
### **Routing Point**
| Attribute | Zoom level: 0 to 11 | 12 | 13 | 14 | 15 |
|---|
| Toid | N | Y | Y | Y | Y |
| Point | N | Y | Y | Y | Y |
| ref_to_itn_road_link | N | Y | Y | Y | Y |
| start_distance | N | Y | Y | Y | Y |
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