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gravitystorm / openstreetmap-carto

A general-purpose OpenStreetMap mapnik style, in CartoCSS
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Distinguishing glaciers by glacier:type, in particular ice shelves and ice tongues #4158

Open c933103 opened 4 years ago

c933103 commented 4 years ago

Looking at the area around 72°S 71°W at mid-zoom levels (~9), where there are both glacier over land and glacier over sea, I found thatit is difficult to tell where are land and where are sea because they're both rendered with same color for glacier. While there are also coastlined but ot's difficult tovtell which part are land and which part are sea. I think it could be distinguished by tuning the color of glacier over sea to be a bit different from.color of glacier over land?

imagico commented 4 years ago

Discussed first back in #646, has been demonstrated how this is done on:

http://maps.imagico.de/#map=9/-72.064/-72.620&lang=en&r=osmlz&o=aa&ui=0

by distinguishing glacier rendering based on glacier:type=shelf and glacier:type=ice_tongue.

For the tagging practice see:

https://wiki.openstreetmap.org/wiki/Antarctica/Tagging https://wiki.openstreetmap.org/wiki/Tag:natural%3Dglacier https://wiki.openstreetmap.org/wiki/Proposed_features/Glaciers_tags

c933103 commented 4 years ago

Discussed first back in #646, has been demonstrated how this is done on:

http://maps.imagico.de/#map=9/-72.064/-72.620&lang=en&r=osmlz&o=aa&ui=0

by distinguishing glacier rendering based on glacier:type=shelf and glacier:type=ice_tongue.

For the tagging practice see:

https://wiki.openstreetmap.org/wiki/Antarctica/Tagging https://wiki.openstreetmap.org/wiki/Tag:natural%3Dglacier https://wiki.openstreetmap.org/wiki/Proposed_features/Glaciers_tags

What about doing it using same principle as methods proposed in #3854?

imagico commented 4 years ago

That does not work here because the mapping practice for floating glaciers and ice sheets is different from that of submarine and tidal coastal features. See the above links for the tagging practice as well as #1540 for current implementation of rendering this in OSM-Carto. Anyway - as said the solution is rather simple since tagging of ice shelves and ice tongues is fairly consistent.

jeisenbe commented 4 years ago

@c933103 thank you for mentioning this. It appears that glacier:type=shelf and glacier:type=ice_tongue are fairly commonly used.

Would you be interested in submitting a PR to start rendering these features distinctively?

jeisenbe commented 4 years ago

@imagico it would be helpful if the tag glacier:type were documented with it's own wiki page, or more fully documented on Tag:natural=glacier, perhaps with some of the text from https://wiki.openstreetmap.org/wiki/Antarctica/Tagging

c933103 commented 4 years ago

@c933103 thank you for mentioning this. It appears that glacier:type=shelf and glacier:type=ice_tongue are fairly commonly used.

Would you be interested in submitting a PR to start rendering these features distinctively?

Sorry, I am not sufficiently familiar with the structure of the style to create a pull request that can achieve a desired result without.

imagico commented 4 years ago

@imagico it would be helpful if the tag glacier:type were documented with it's own wiki page

Yes, probably.