Geonames.org: My Favorite Geo Data Provider
Geonames.org is an excellent web site for one-stop shopping of geospatial data. It features about 2.2 million records of geographical information. This includes data from
- NGA Geographic Names Database (GNDB)
- NGA US Board on Geographical Names
- U.S. Geological Survey Geographic Names Information System
- GeoBase data of Canadian geographical feature names
- Wikipedia, elevation of mountains, world population data etc.
Many reasons why Geonames.org is interesting:
First, it provides a unified representation of geographical data from different providers. For example, a client queries for geo information about “London”, in the same query response, the service returns the lat/long of the city, feature class names, population, administration code/names, and country code/name.
Second, it provides web service API for querying geographical information. The Geonames web service implements the simple REST framework. To query the service, clients access a specific URL with configurable query parameters. For example, the basic “search” service has configurable parameters such as “country” (search within a particular country code), “fcode” (search within a particular feature code), and “style” (the verbosity of the search results). Here is an XML query for information about “London”.
Third, Geonames web service supports both JSON and XML output. Given that JSON is the de facto data representation standard in Web 2.0 applications, Geonames has done the heavy lifting to prepare and manage geographical data for lightweight Web 2.0 applications. Here is a JSON query for information about “London”.
Geonames website features a number of different mashup applications that utilize its geo data provider service. All Geonames data is free under the Creative Common License. If you want to get a copy of the data, there is a breakdown of the data in 230 zip files.
