Changed rendering order of water areas breaks supraglacial lakes

[imagico]

In dc108c3 the render order of water areas (including glaciers) was inverted with respect to way_area resulting in supraglacial lakes (lakes on a glacier) to not be visible any more. Example: http://www.openstreetmap.org/way/279649918

Generally the natural order of glaciers/water would be water above glacier since water is by definition a surface feature.

[matthijsmelissen]

@pnorman Did you change the ordering for any particular reason?

[dieterdreist]

Am Samstag, 13. September 2014 schrieb imagico :

Generally the natural order of glaciers/water would be water above glacier
since water is by definition a surface feature.

Isn't this true for glaciers as well (surface feature)?

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[matkoniecz]

And there are also subglacial lakes.

[imagico]

@dieterdreist - not necessarily, a glacier is just a body of ice, there can be all kind of things on top of it.

@mkoniecz - that is not the issue here, underground features are always distinctly tagged and an underground waterbody would not be correct as natural=water. Apart from that mapping of subglacial lakes in OSM would be questionable due to lack of verifiability.

[dieterdreist]

2014-09-14 20:42 GMT+02:00 imagico notifications@github.com:

@mkoniecz https://github.com/mkoniecz - that is not the issue here,
underground features are always distinctly tagged and an underground
waterbody would not be correct as natural=water. Apart from that mapping of
subglacial lakes in OSM would be questionable due to lack of verifiability.

the wiki definition for natural=water doesn't require overground location,
it requires a body of standing water, so I think an underground lake could
be tagged natural=water and location=underground, not sure how likely it is
to find them underneath a glacier but this German wikipedia page mentions
lakes below a glacier: http://de.wikipedia.org/wiki/Eisstausee

[imagico]

A subglacial lake is not a body of standing water, it is a pocket of liquid water enclosed between glacier ice and bedrock.

Lets lot confuse the issues - an area tagged natural=water without supplemental tags within an area natural=glacier should be drawn on top - i see no basis for a different approach. This has been done correctly (not on the basis of tagging but on the basis of size - the effect however is the same). If there is a reason for inverting the rendering order with respect to size i would suggest introducing an additional sorting criterion based on tagging, otherwise just restore the previous sorting.

Side note: in general and independent of this particular issue i think sorting 'smaller on top of larger' is better with no other matters weighting in since it is less confusing for the mapper.

[pnorman]

@pnorman Did you change the ordering for any particular reason?

No, it was inadvertent. I didn't spot it in the JSON diff.