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<div class="moz-cite-prefix">On 31/05/2019 11:26, Paul Allen wrote:<br>
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cite="mid:CAPy1dOKVwY9NThyPZgV9Sj+y+1_4LAFZ73+pzk8RpbfjBt3RTw@mail.gmail.com">
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<div>Example of the horrors of using canal for a leat with
current carto:</div>
<div> <a
href="https://www.openstreetmap.org/way/609805692#map=16/52.0804/-4.6799"
moz-do-not-send="true">https://www.openstreetmap.org/way/609805692#map=16/52.0804/-4.6799</a></div>
<div>At z=19 it's actually close to the true width of the
leat.<br>
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<p>I suspect that the OSM Carto style would be open to pull requests
that looked at the sub-tags of canals etc. if it could be done in
a way that wasn't over-complicated - look at OSM Carto's handling
of leaf type for a possible way forward.</p>
<p>A bigger problem is the lack of granularity of rendering width at
various zoom levels (see for example
<a class="moz-txt-link-freetext" href="https://www.openstreetmap.org/#map=13/54.1856/-0.8334">https://www.openstreetmap.org/#map=13/54.1856/-0.8334</a> ,
<a class="moz-txt-link-freetext" href="https://www.openstreetmap.org/#map=14/54.1850/-0.8258">https://www.openstreetmap.org/#map=14/54.1850/-0.8258</a> and compare
with
<a class="moz-txt-link-freetext" href="https://map.atownsend.org.uk/maps/map/map.html#zoom=14&lat=54.18504&lon=-0.80956">https://map.atownsend.org.uk/maps/map/map.html#zoom=14&lat=54.18504&lon=-0.80956</a>
).<br>
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<p>To cut the OSM Carto folks some slack, they're trying to
implement a global rendering style that has to cope with (in this
case) all of the different sorts of waterways everywhere on the
planet. There are always going to be places where a certain
feature is densely mapped and where it is important but isn't -
look at the way that highway=footway becomes essentially invisible
at zoom levels where it would be really useful (in rural areas)
because it would overwhelm the map elsewhere (central European
cities). I'm sure that they'd be open to a pull request that
addressed the stream width issue above, but it'd need to be tested
elsewhere on the planet - and I'm sure that there are places where
the presence of a stream is "literally the most important thing on
the map" at z14.<br>
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<p>I therefore wouldn't use OSM Carto as an example of "here's what
you get when you tag <feature> as X". Often there's a
specialist map somewhere designed to show <feature>, and
that's probably the better option where it exists.</p>
<p>Best Regards,</p>
<p>Andy</p>
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