After 14 days on the Warwickshire ring with my EeePC running Tangogps and recording my track for OSM, I was disappointed to see that although locks are marked on the map, they don’t show up either on mapnik or osmarender, I had to resort to Google to see where the locks were. Where do I submit a request that locks be added to the render engine?
I noticed when looking at the edit screen that some locks seem to be tagged as lock, some as the gates and some both. Which would be the recommended way of tagging?
The place to request the rendering is on OSM Trac. File it under Mapnik.
I’m not fully confident in the proper way of tagging of locks yet so I won’t try to answer your second question. Hopefully Richard Fairhurst will spot your question but if not it might be worth you contacting him.
My preferred way of tagging locks (in the UK, where - Manchester Ship Canal aside - they’re never big enough to merit an area) is just to put lock=yes on the node.
Creating a separate way, with a lock-gate node at each end, seems to me like a needless complication and also implies an accuracy that isn’t there. In particular, that implies that the distance between the gates is significant; but on the British waterways, the difference between a 70ft lock and a 72ft lock is absolutely crucial for some boats, and the mapping is unlikely to be that accurate. So it’s much better to tag lock=yes on the node, and add maxlength=72ft.