Flesh out README a little

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Eric Fischer 2015-03-06 14:32:53 -08:00
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tippecanoe tippecanoe
========== ==========
Build vector tilesets from large collections of GeoJSON features. Builds vector tilesets from large collections of GeoJSON features.
Intent
------
The goal of Tippecanoe is to enable making a scale-independent view of your data,
so that at any level from the entire world to a single building, you can see
the density and texture of the data rather than a simplification from dropping
supposedly unimportant features or clustering or aggregating them.
If you give it all of OpenStreetMap and zoom out, it should give you back
something that looks like "[All Streets](http://benfry.com/allstreets/map5.html)"
rather than something that looks like an Interstate road atlas.
If you give it all the building footprints in Los Angeles and zoom out
far enough that most individual buildings are no longer discernable, you
should still be able to see the extent and variety of development in every neighborhood,
not just the largest downtown buildings.
If you give it a collection of years of tweet locations, you should be able to
see the shape and relative popularity of every point of interest and every
significant travel corridor.
Installation Installation
------------ ------------
@ -56,6 +77,10 @@ For point features, it drops 1/2.5 of the dots for each zoom level above the bas
I don't know why 2.5 is the appropriate number, but the densities of many different I don't know why 2.5 is the appropriate number, but the densities of many different
data sets fall off at about this same rate. You can use -r to specify a different rate. data sets fall off at about this same rate. You can use -r to specify a different rate.
You can use the gamma option to thin out especially dense clusters of points.
For any area that is denser than one point per pixel (at whatever zoom level),
a gamma of 3, for example, will reduce these clusters to 1/3 of their original density.
For line features, it drops any features that are too small to draw at all. For line features, it drops any features that are too small to draw at all.
This still leaves the lower zooms too dark (and too dense for the 500K tile limit, This still leaves the lower zooms too dark (and too dense for the 500K tile limit,
in some places), so I need to figure out an equitable way to throw features away. in some places), so I need to figure out an equitable way to throw features away.
@ -83,3 +108,8 @@ and sqlite3 (apt-get install libsqlite3-dev). To build:
and perhaps and perhaps
make install make install
Name
----
The name is [a joking reference](http://en.wikipedia.org/wiki/Tippecanoe_and_Tyler_Too) to making tiles.