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Document how to choose high-zoom dot sizes

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Eric Fischer 2015-03-26 11:25:56 -07:00
parent 3d074653b5
commit 0cd733eb77
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README.md
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@ -67,6 +67,30 @@ Example
cat tiger/tl_2014_*_roads.json | tippecanoe -o tiger.mbtiles -l roads -n "All TIGER roads, one zoom" -z12 -Z12 -d14 -x LINEARID -x RTTYP
Point styling
-------------
To provide a consistent density gradient as you zoom, the Mapbox Studio style needs to be
coordinated with the base zoom level and dot-dropping rate. You can use this shell script to
calculate the appropriate marker-width at high zoom levels to match the fraction of dots
that were dropped at low zoom levels.
awk 'BEGIN {
dotsize = 2; # up to you to decide
basezoom = 14; # tippecanoe -z 14
rate = 2.5; # tippecanoe -r 2.5
print " marker-line-width: 0;";
print " marker-ignore-placement: true;";
print " marker-allow-overlap: true;";
print " marker-width: " dotsize ";";
for (i = basezoom + 1; i <= 22; i++) {
print " [zoom >= " i "] { marker-width: " (dotsize * exp(log(sqrt(rate)) * (i - basezoom))) "; }";
}
exit(0);
}'
Geometric simplifications
-------------------------