Re: really huge relations. The Great Lakes are mapped (and rendered) with multipolygon relations.
Also, the even bigger island of New Guinea has all of its coastline included in a multipolygon. I don’t know about Greenland or Madagascar, but I believe it would be considered correct to map them in this way. The key difference for OSM is that an island is verifiable as a landmass surrounded by water, while a bay is indefinite on one side. On Sun, Nov 18, 2018 at 8:36 PM Joseph Eisenberg <joseph.eisenb...@gmail.com> wrote: > Christoph, I was really looking forward to hearing how we can render good > labels for bays and seas, based on a node and the coastline. > > Is there any possible solution the would work with Mapnik and CartoCSS? > > Perhaps computing the shortest distance between the bay node and coastline > would somehow work for a rough label size on low zoom levels? > > Or could this data be included in the generalized water polygons at > openstreetmapdata, or the shapefiles used by openstreetmap-carto, somehow? > > On Sun, Nov 18, 2018 at 8:06 PM Christoph Hormann <o...@imagico.de> wrote: > >> On Sunday 18 November 2018, Eugene Alvin Villar wrote: >> > [...] >> > >> > As a sort of compromise at least for bays (gulfs, inlets, fjords, >> > coves), how about we just map them as a single way across the mouth >> > of the bay and not as a way-polygon nor type=multipolygon relation? >> > And then we set the direction of the way such that the right-hand >> > side of the way points to the bay-side (just like the right-hand side >> > of natural=coastline ways point to the seaward side). >> >> While this obviously has the same verifiability issues as the polygon >> drawing in general (you already say that) this is actually a great >> demonstration for the core of the problem. >> >> It can be explained with the following formula: >> >> >> polygon mapping of bays/straits using the coastline as components >> >> *equals* >> >> coastline data already mapped anyway >> >> *plus* >> >> completely subjective data about a non-verifiable limit of the >> bay/strait >> >> >> Mapping only the last part should satisfy all those who disagree that >> there is no additional verifiable information in the polygon mapping of >> bays (because whatever is in there would be contained in this form of >> mapping - see the above formula). >> >> It will however likely not satisfy most because: >> >> * The "map designers who want to outsource label drawing to the mappers" >> and "mappers who want to draw labels" will have difficulties acutally >> performing above addition (because as mentioned: coastline data is not >> in the database and the operation to select and assemble the data as >> needed is not cheap). >> * The "everything is to be mapped with a polygon" proponents will not >> like this because it is not a readily assembled polygon, just a >> component of it, therefore insufficient for a purist. >> * The verifiability proponents (like me) will dislike adding >> non-verifiable data to the database but this is much less harmful than >> the polygon drawing so i clearly see it as the lesser of two evils. It >> nicely separates the verifiable data from the non-verifiable data so it >> definitely is the most acceptable form of non-verifiable mapping in OSM >> (if there is such a thing). >> >> As a data user - while this is more difficult to process than a node >> based mapping it would be manageable. >> >> Long story short: What i like about this proposal is that its rejection >> will bring clarification on the motives for the different opinions >> pursued here. What arguments you have against this suggestion will >> decide which of the above groups you belong to. ;-) >> >> -- >> Christoph Hormann >> http://www.imagico.de/ >> >> _______________________________________________ >> Tagging mailing list >> Tagging@openstreetmap.org >> https://lists.openstreetmap.org/listinfo/tagging >> >
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