From OpenStreetMap Wiki
|bay = fjord|
|Long, narrow inlet with steep sides or cliffs, created by glacial erosion.|
|Used on these elements|
|Tools for this tag|
- See on Wikipedia
Note: Fjords can exist both in the sea and in freshwater/lakes.
How to map
The following guidelines are proposed:
- large fjords (such as the 179 km long on Wikipedia) should be mapped as area/polygon, following the coastline along land, but using a simplified geometry.
- smaller fjords should be mapped as area/polygon, either coinciding with the coastline or as a multipolygon using the coastline directly.
- narrow fjords without branches may be mapped using a way, but an area is preferred.
- small fjords may be mapped using a single node, but an area is preferred.
- fjords should in general be mapped as linear ways.
- branches with names may have a separate way connected to the main branch/trunk of the fjord.
- branches may be collected in a relation, together with the main branch/trunk of the fjord, in order to indicate separate names for each branch but still indicate which fjord they belong to.
- small fjords may be mapped using a single node, but a linear way is preferred.
- mapping fjords as areas instead of ways is permitted, but not recommended.
Pros and cons:
- The "simplified geometry" of large fjords (in Alt.1) will generate some redundancy (since the more detailed coastline is already there).
- The "simplified geometry" of large fjords (in Alt.1) may make it harder to maintain.
- Using ways (Alt.2) is faster and easier than making a separate simplified area (Alt.2).
- Using area (Alt.1) instead of a linear way (Alt.2) gives a better "importance" calculation, e.g. for a (relatively) short and wide fjord compared to a long and narrow one with the same approximate area.
- Using area (Alt.1) instead of a linear way (Alt.2) makes it possible to detect whether e.g. an island or a fish farm is in a specific fjord.