✍ a short introduction
@tmcw + @aj_ashton / MapBox
Yes! Some of the best data is government-generated and free.
The US Census TIGER dataset makes up most of America?
Maybe! Ask on https://bit.ly/osm-import
OpenStreetMap data rivals commercial providers.
In some areas, it's more complete - and in some it's
less. But unlike other maps, this one you can improve.
You can download the whole thing:
Free as in: not only $0, but you can adapt
it, download it, print it, and more.
What's in it?
the key to understanding openstreetmap: it's a single, global
effort. not just a dumping ground for data.
made up of nodes
aka LineString and Polygon
a group of ways → a multipolygon
* no real GIS equivalent...
the basic form of a tag:
so nodes, ways, and relations are the basic elements
of OpenStreetMap, and each can have data attached to them
one last thing
are our version of history
a changeset is a group of changes
user tmcw changed way #1000, adding
a tag and removing a node.
this answers the question of vandalism: yes,
it happens, but we know who does it and we can reverse the