Getting started: DATA

Before you begin:

• Setup your PostGIS database

Sources of Data:

• Detailed neighborhood streets, highways, rail, paths, and points-of-interest (POI) data comes from OpenStreetMap.
• General world and regional scale map data such as countries or states comes from Natural Earth.
• Detailed place names come from GeoNames, which collate them from a variety of sources. USGS and US Census are also good sources.
• Digital elevation, landcover and similar data comes from US Geological Survey.
• US statistical divisions like metro areas or counties come from US Census.

The first three are global in scope, the last two are mostly US-only, alternatives exist on a per-country basis.

Often data is pre-process to prepare it for rendering. Sometimes to make it look a certain way, other times to make it run faster.

Open Street Map

###Extractotron

• Get OSM data extracts for big cities world wide in small chunks (mb instead of gb). Updated monthly.

• http://metro.teczno.com/

###OSM Planet

• The big kahuna. You'll need a beefy machine. Updated daily.

• For making detailed city maps from zooms 12 to 19+.

###Importing OSM

• Osmosis - Parsing and merging large Planet or other XML and binary OpenStreetMap data files.

• osmfilter - Similar.

• osm2pgsql - Get raw OSM files into PostGIS databases.

• High Road - Add views into the data, grouping ways into large, medium, and small roads per zoom.

Gotcha's

• High Road - Important to drop and then readd this on each OSM import. Details on the High Road page.

##Natural Earth

• NaturalEarthData.com - For making generalized world maps from zooms 0 to 8.

Help getting Natural Earth into PostGIS

• Aaron's Naturalearth-tools - Shell script for fetching the data, clean-geometry, and reprojecting to web Mercator from Aaron

##Other data

• Often you can get GIS map data from your local or state government.

##Considerations

• Does your basemap need to reflect the latest edits?
• Do you cover a rapidly expanding urban area where the roads change all the time and you're users will notice?
• Will you re-render your basemap on a never, yearly, monthly, weekly, daily, frequency?
• World up to a certain zoom then just your local geography?