Geographical data resources online

This page collects online resources that provide geographical information, in the widest sense. So information on postal codes or the locations of IP addresses is also included. I'm most interested in data related to Germany.

Map data

DCW - Digital Chart of the World - provides different types of data for all countries. Includes polygons with country outlines, and more detailed information on roads, waterways etc. Data is from 1991 / 1992. No login required. [Free]
GTOPO30 data set - elevation data. [Free]
U.S. Census Bureau - Cartographic Boundary Files (USA) - map data for different types of administrative divisions of the USA, e.g. congressional districts or urban areas. [Free]

Places and regions

OpenGeoDB - places and their coordinates in Germany, Switzerland and Austria. Available for download as text file and SQL dump. This is an open project, a work in progress that requires help of interested people. Check out the OpenGeoDB mailing list. [Free]
How many countries are there in the world? - an overview of the different organizations that deal with country codes. Not a data resource, but a good introduction. [Free]
GeoNames—one ZIP file for every country, with places and their longitude/latitudes. Has postal codes for various European countries. Also allows online queries, see the GeoNames homepage. [Free]
GeoDataSource Database of places, their names and coordinates. Different version from free over basic to premium and gold. [Commercial, free version available]
GEOnet Names Server (GNS) — free lat/long information on places around the world (excluding USA and Antarctica) as text files. Complete download is about 200 MB. [Free]
FIPS 10-4 / Federal Information Processing Standards Publications (FIPS PUBS) 10-4 - contains subcountry codes. Countries typically are subdivided into regions of some sort, for administrative purposes. In the US, there are states, Germany has the “Bundesländer”, others call them provinces, districts, regions, etc. The FIPS 10-4 list contains the English names of all those regions for all countries, plus a unique code for each of the regions. The codes are made up of two characters for the country plus two alphanumeric characters for the region. Examples: US23 is Maine, USA, GBZ1 is Swansea, United Kingdom, GM02 is Bavaria, Germany. The list is maintained by the US governmental institution NIST. The Maxmind.com version of this list is probably nicer to parse. [Free]
ISO 3166-2 - a list of codes for administrative subdivisions of all countries listed in ISO 3166-1. Similar to FIPS 10-4 (see above). The Wikipedia 3166-2 entry has more background information. Official code list seems to be unavailable for free - see this page for database prices. There is an unofficial list of ISO-3166-2 codes, which unfortunately has some codes changed (Great Britain is no longer GB but UK - probably those countries with an Internet country top level domain differing from ISO-3166-1 were changed). [Commercial]
List of countries and territories - Names of countries and territories, plus various codes, including ISO 3166-1 / -2, UN numerical codes, Internet country codes. Also information on whether the state still exists and is sovereign. [Free]
Thomas Mack's download page - lists of German cities and towns, including their lat/long coordinates, their postal codes and the regions (Bundesländer, Regierungsbezirke, Landkreise, etc.) that they belong to. Offers a list of Portuguese cities as well. [Free]
Dutch places, municipalities and provinces - not computer-readable. [Free]
UK waypoint database - a collection of British hills as MS Access database (.mdb) by Phil Newby. [Free]
United Nations (UN) statistics division - Offers various lists with numerical codes:
[Free]
US cities - text file with rows containing city name, state code, latitude and longitude. This list is distributed to be used with IPtoLL. [Free]
IOC Offizielle Länderabkürzungen - official language codes for the International Olympic Committee. [Free]

Imagery

California Coastal Records Project - Provides photos of the complete (with the exception of the area of one military base) Californian coastal line, taken from a helicopter. There is Lat/Long information in the high resolution versions of the JPEG files, more specifically in their respective EXIF headers, describing the position where the image was taken. About 12,000 photos, each about 4 to 8 MB. [Free]

Software

Image_GIS - PHP code to render maps from Arcinfo/E00 files. [PHP license]

Geolocation: map IP addresses to locations

Each computer connected to the Internet has an address to identify it within the network. For Web site owners it's interesting to know where exactly their visitors are from (for targeted advertising, adjusting the content, fraud prevention etc.).

A CNN.com article gives some background on technology, uses and risks: Geolocation tech slices, dices Web (2004-07-12).

GPS-Based Addressing and Routing - 1996 article by Tomasz Imielinski and Julio C. Navas on integrating GPS geo information into the Internet Protocol.
Hostip.info - map IP addresses to cities. Includes database download, XML/SOAP API, visualization applet. [Free]
IPGEO a free online service, including API, to map IP addresses to city and country.
IP Country Lookup— free Windows tool with own database which maps IP addresses to countries.
IP index - information on IPv4 network block owners. Data was retrieved via whois and somewhat outdated. Page contains an e-donkey link to an archive with a full website dump (22 MB). [Free]
ip2ll - web interface to retrieve lat/long information for a given IP address or hostname. [Free]
IP2Location - IP to geographical location mapping [Commercial]
localizer - database with location information on about 40 million IP addresses in Germany, Switzerland and Austria. Data or services to access the database online are available. [Commercial]
Quova sells data and services around its self-assembled database. Self-proclaimed industry leader. [Commercial]
RIPE database - Contains a compressed text file ripe.db.gz (~ 60 MB) with a database dump of allocation information of Internet address blocks. [Free]
WEB-GPS - project to collect lat/long information for IP addresses. No data download. [Free]
Webhosting.info IP-to-Country database and tools - looks up a country for a given IP address, additional tools [Free]

Literature

Geodaten im Internet - Ein Überblick - Article by Gunnar Teege in Informatik Spektrum 4 / 2001. [PDF full text for subscribers only]

Postal codes

Großempfänger-Postleitzahlen / German postal codes for large enterprises and institutions (they get their own postal codes once they receive more than 1000 deliveries per day. List as of 1993-12-01. [Free]
Old and new German postal codes - Perl code and postal codes for Germany, both the old four-digit codes and their corresponding new codes (valid since July 1993) are included. [Free]
Germany - also see the OpenGeoDB project linked to above. [Free]
Belgium - postal codes and city names - the data is basically text without any HTML formatting. [Free]
UK postal codes - each line contains name, county and postal code for one British town. [Free]
France - various data collections, including cities, regions and postal codes. [Free]

Miscellaneous

Degree Confluence Project - not really a data resource, but geo-related and a lot of fun to browse. Mission statement: The goal of the project is to visit each of the latitude and longitude integer degree intersections in the world, and to take pictures at each location. The pictures and stories will then be posted here. [Free]