[OSM-talk] Request for feedback: new building colours in openstreetmap-carto
chris_hormann at gmx.de
Tue Jan 6 18:20:01 UTC 2015
First i do not particularly like or dislike the new color, looking at
this change only it seems to me in some areas and zoom levels the map
appearance is improved, in others it is not.
But as i have mentioned on github i think in a broader consideration
regarding the style as a whole this change goes in the wrong direction.
Making the buildings much lighter further restricts the available color
space for area colors (that is essentially all colors that could form a
background to a building). The available space between the background
color of the map and the building color is extremely small to fit into
that dozens of different area colorings and still be distinguishable.
So far no suggestion has been made to address this i think.
We all know that the standard map style has a lot of technical
constraints that make a good design difficult but you should not make
the mistake to avoid hard decisions by creating ambiguities. The
clarity of a map strongly depends on things that are shown to be
clearly and distinctly shown and not too much stuff that is just
Specifically this is a problem when showing buildings at zoom levels
12-14 where the individual building often is hardly 1-2 pixels in size.
In areas near the equator (where extensive building mapping is rare)
showing buildings at z=12 is fully pointless and still doubtful for all
but the largest buildings at z=14, see:
Even at very high latitudes at z=12 the smaller buildings are just
And in areas with dense building coverage this is further aggravated by
the way AGG renders polygons.
From z=15 on things look better, largely due to the outlining - low
latitude cities still look crappy but more due to the roads than due to
Part of why the brighter color might seem an improvement is that it
creates less disturbing noise at these levels but this is just hiding
the fact that displaying sub-pixel sized buildings does not make a lot
of sense and it further smudges the already difficult to distinguish
urban landuse colors.
In any case ultimately i think it is good to try things out this way -
there is only so much you can evaluate in advance in a test deployment
as it has been done for this change.
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