Current wiki guidance for tagging slipways (leisure=slipway) is as follows:

A typical mapping might be to make a short highway=service way to the water’s edge and make the final node a leisure=slipway.

The highway=service that is part of the physical slipway is often further refined with a service=slipway. Keep in mind though that this does not replace leisure=slipway, mapped as a node on the end of that way.

Some mappers instead tag the whole way as leisure=slipway without using a highway=* tag, or sometimes in combination with highway=service (here service=slipway can be applied as well as above).

In other words there are two options (the first being implicitly preferred)

Option 1 - tag the node

• way: highway=service + service=slipway
• final node: leisure=slipway

Option 2 - tag the way

• way: leisure=slipway + optional highway=service + service=slipway
• final node: not tagged

The map marks an icon for both nodes and ways tagged with leisure=slipway. It’s therefore likely not advisable to do both. But which one is preferable?

There is some discussion about this on the wiki but no apparent resolution and it appears to refer to previous versions of the guidance: osm.wiki/Talk:Tag:leisure%3Dslipway

Though there is a question raised about wether leisure=slipway should be replaced by highway=service + service=slipway outright, especially given not all slips are for leisure use. But the map only marks an icon for leisure=slipway so this is likely not recommended.

Status quo

I wrote a script to analyse the data from of an area on the south east coast of Scotland.

https://overpass-turbo.eu/s/2hdk

The results:

• 45: option 1 (includes 16 orphaned nodes with no way)
• 62: option 2

So option 2 appears to be preferred, however it results in the map icon being placed at the mid point of the slip.

For ways that are correctly scoped to just the sloped slipway, this is probably ok. Longer ways should be split anyway.

But tagging the final node could be a more useful map display in some cases.

What do other mapping services do? I don’t have large enough scale Ordnance Survey maps or otherwise to hand to be able to tell properly. My Imray chart seems to place the slip icon at the end of the slip but the scale is relatively small.

The one thing that feels clear is that we should only use leisure=slipway on either the way or final node, not both. Also, ways should be properly scoped and nodes should have an associated way.

Details

Analysis script: https://gist.github.com/jwheare/a3577de092c68b1789e454e832b38f5b

Note: this script takes as input the raw OSM data passed through osm2geojson.json2geojson https://pypi.org/project/osm2geojson/ (it doesn’t currently handle overpass-turbo GeoJSON directly)

Overpass query:

https://overpass-turbo.eu/s/2hdk

[out:json][timeout:90][bbox:55.37911,-4.21875,56.944974,-1.40625];
(
  // nodes only
  node["leisure"="slipway"];
  // ways that contain the above nodes
  way(bn)["highway"];
  // all nodes/ways/relations
  nwr["leisure"="slipway"];
  nwr["service"="slipway"];
);
out geom;

Appendix

Node not tagged (62)

• 35: leisure=slipway highway=service service=slipway ✅ perfect option 2
• 25: leisure=slipway
  • could add highway=service + service=slipway
• 2: service=slipway highway=service
  • doesn’t use leisure=slipway at all, should be fixed (done)
    • way/1012902378
    • way/1346501677

End node tagged (29)

• 15: highway=service
  • could add service=slipway
• 9: highway=service service=slipway ✅ perfect option 1
• 3: leisure=slipway highway=service service=slipway
  • double tagged, should be fixed (done)
• 1: highway=footway
  • way/57775872
  • long footway that ends in a slip. should be split up into two separate ways (done)
• 1: highway=service service=driveway
  • way/129911891
    • short driveway that ends in a slip. should be split up into two separate ways (done)

Start node tagged (8) (way should be reversed - done)

• 6: highway=service
  • could add service=slipway (done)
• 1: leisure=slipway highway=service service=slipway
  • double tagged, should be fixed, but complicated arrangement so unclear which option is best
    • way/210856759
• 1: highway=path
  • long path that ends in a slip, with the start node. should be split up into two separate ways with the slip reversed (done)
    • way/978785415

Some other node tagged (4)

• 2: highway=service
  • way/327317264
    • long track that ends in a slip, with the node tagged in the middle. should be split up into two separate ways (done)
  • way/626239129
    • doesn’t need to be split, but node should be moved (or removed and way retagged) (done)
• 2: highway=track
  • way/887901902
    • mistagged car park with a slip at a point where it meets water. should have a separate way added for the slip (done)
  • way/499488192
    • long track that ends in a slip, with the node tagged at the top. should be split up into two separate ways (done)

Stats

• nodes: 56
  • orphans: 16 (way should be added)
• ways: 103
  • leisure=slip node missing: 62
  • leisure=slip node at start: 8
  • leisure=slip node in middle: 4
  • leisure=slip node at end: 29
• way tags
  • highway=service (74)
  • leisure=slipway (64)
  • service=slipway (50)
  • highway=track (2)
  • highway=footway (1)
  • service=driveway (1)
  • highway=path (1)

Changesets made to fix various issues mentioned here:

• changeset/175892606
• changeset/175893398
• changeset/175893662
• changeset/175894013
• changeset/175894979
• changeset/175895389
• changeset/175896209
• changeset/175897032