Oh, and btw, you broken the global coastline processing. See https://tools.geofabrik.de/osmi/?view=coastline&lon=8.45358&lat=4.73407&zoom=15&baselayer=Geofabrik%20Standard&overlays=coastline

Looks like you have been mapping parts of what is clearly the sea as inland water. Please revert this. You can not just arbitrarily make a line somewhere and say sea is on the one side and inland water on the other. It isn't always easy to say where the line is exactly, but certainly not where you have drawn it. Hint: if it is tidal than it is part of the sea.

There are now two coastlines around the Eastern Neck National Wildlife Refuge. This creates all sorts of problems. See https://tools.geofabrik.de/osmi/?view=coastline&lon=-76.21293&lat=39.03022&zoom=14 . Can you fix that, please?

And please don't put "Do not delete" notes on everything. That wil just clobber the database with useless stuff.

That's more than a few errors that just have crept in. And editors have powerful checkers to find problems.

Your import is has resulted in quite a lot of broken data. Many island you imported were already there. Please fix the data! You can see the problems here:

https://tools.geofabrik.de/osmi/?view=coastline&lon=7.14292&lat=59.10386&zoom=7

Ups. Sorry. Fixed.

You are breaking >10 years worth of software, style sheets, maps, etc. Everybody who has dependet on this definition. This is not something you can change.

The way the natural=coastline tags have been understood for the last >10 years clearly say that the coastlines tags should go around the bay. Some of the details of the discussion on the tagging mailing list do not matter for the situation here. Are you going to revert this now?

I personally don't have an opinion on any tagging here except that natural=coastline should be where it used to be. If you want other tagging for naming the Bay that's fine with me.

Sorry, Sparks, but it doesn't matter for OSM what something "is". All that matters is that we agree on tagging, so that everybody can use the data consistently. And the agreed definition on where natural=coastline is tagged is in the wiki and has been used for a long time. You can not change this without breaking a whole lot of usage of the data. You are free to invent new tags that mean a different thing, but you can not change existing definitions. (Well, you could, but in something like this it would take quite a lot of community discussion and a worldwide consensus which would be very hard to reach.)

Lake Michigan is an actual lake, not part of the sea, so it doesn't apply here.

You can not just change what a tag is supposed to mean that has been around for years. Such changes break OSM. You just have to look at a map like the cycle map: osm.org/#map=4/43.13/-94.83&layers=C It doesn't show the great lakes in small zoom levels and it will not show Chesapeake Bay in the future any more of this change stands.

I am not sure what you mean with "follows the bathymetry of the Bay". The wiki defines the coastline as "The natural=coastline tag is used to mark the mean high water springs line along the coastline at the edge of the sea." By that definition your coastline is way off.

This change breaks the whole world map! The Chesapeake Bay is a bay but it is still part of the sea, not an inland water area. The bay is clearly tidal, clearly part of the sea, so the natural=coastline tags have to go around it. On many maps this huge area will now not be visible as water any more, because many maps don't render inland water until larger zoom levels. This change is also blocking updates to *all* coastlines around the world, because the automatical coastline tool has noticed this huge change in the world map. See
https://osmdata.openstreetmap.de/internal/coastline/

The coastline in this area is broken. See https://tools.geofabrik.de/osmi/?view=coastline&lon=-76.51587&lat=36.88312&zoom=12

Not sure whether it was this changeset or another. Can you have a look?

These overcomplex multipolygons are currently not fixable, because the software used to interpret them can't handle these complex cases. And every time you change them, there is a chance the processes handling them break. So please, at least for the time being, stop editing them. We have to figure out how to make the software work correctly.

The wiki says "The natural=coastline tag is used to mark the Mean high water spring which is the point of the highest tide." This implies that there is a tide...

If you think about where you want the coastline to be drawn on small zoom levels, where the sea is drawn but inland waterbodies aren't it becomes clearer where it makes sense to draw the coastline.

This change turns huge ocean areas into an "inland water" by putting the coastline far out. Is this correct? Generally water areas that are tidal should probably be mapped as part of the sea.

The changeset comment suggests that this changeset is about the "Closed_ways_with_spikes" I created. But there are a lot of edits here that might be due to a misunderstanding. This challenge is not about turning circles or turning loops! I don't want to say anything about whether it is right or not to turn turning loops that are mapped in detail into single points, but it definitely hasn't anything to do with the challenge. Is there some misunderstanding about the purpose of the challenge here? Or is this some other mapping that was done without changing the changeset comment?

You can also see the problem here:
http://tools.geofabrik.de/osmi/?view=areas&lon=1.34089&lat=43.57942&zoom=17

There are over 700 duplicated nodes here! JOSM finds thousands of errors with the validator.

This changeset broke the coastline. See http://tools.geofabrik.de/osmi/?view=coastline&lon=57.26229&lat=25.95029&zoom=18&overlays=coastline,coastline_error_lines,line_not_a_ring,line_overlap,line_invalid,line_direction,questionable,coastline_error_points,unconnected,intersections,not_a_ring,double_node,tagged_node . Problem is overlapping coastlines. Is the new border/coastline really correct? Sat images show a different coastline. Are boundary and coastline really the same here and at the new location? Also there are obviously far too many changes in this changeset for a manual inspection. Changes should be put into smaller changesets. And changing the old coastline to tagging natural=xxxcoastline is not a good idea. You have to conflate the old and new data in one go and not just put your new data over the old and then later maybe fix it.

Interessant. Ich hab keine Ahnung mehr, wie das zustande kam. Mein GPS schreibt keine Höhenangaben in die GPX-Datei und ich kann mich auch nicht erinnern, jemals ele-Tags benutzt zu haben. Verbuchen wir es mal unter Anfängerfehler. :-)