From OpenStreetMap Wiki
This is a proposal for renderer / API hint relations.
Problem: Large areas may not be rendered if the area is surrounding but not touching the requested bounding box. [example]
proposed Solution: Create a "hint" relation and adapt API or renderer!
|type||hint||defines the type of the relations|
|Way or Node||Role||Recurrence?||Discussion|
|pointer||1+||hint node(s): one inside every Z12 tile not rendered correctly|
|target||1||the area the hint is pointing at|
- adapt renderer to load referenced way in preprocessing and merge it into data file or
- adapt API to include the referenced way in output.