Google GI Services

In 2004 and 2005, Google launched a series of searching and mapping facilities that allowed some degree of geographic information retrieval. While the services provided were not original (e.g. existing mapping data licenced from Tele Atlas, 3d software through purchase of Keyhole), the scale, scope and implementation of the services is beginning to have some major impacts on the use and sharing of GI.

In particular the following are likely to contribute to Google's impact:

• The API of the mapping software is published and available to all.
• Google maps and google local require no extra software other than a browser to function
• The scale of data purchase and distribution is huge (e.g. global mapping; large scale street mapping in much of developed world; global satellite mapping; selected high resolution areal photography; postcode and gazetteer databases etc.)

Official Google Sites (UK)

• http://maps.google.co.uk Google maps home (currently an alias for maps.google.com).
• http://earth.google.com Google Earth home (3d interface to Google's GI).
• http://local.google.co.uk Google Local (spatial gazetteer and search engine).

Some Examples of Alternative Services

• www.streetmap.co.uk Mapping with gazetteer service.
• virtualearth.msn.com Microsoft's answer to online web mapping (perhaps they should put 'Some experience of cartography required' next time they employ someone).

Some of my Experiments with Google Maps

The following examples show how the recently published Google Maps API can be used to generate shared mapping for the web. Click link and 'view source' to see how the map is produced.

• Basic map. Simple equivalent to 'Hello World' showing the basics of linking to the google map script.
• Simple polygon example. Overlay of polygons on a google map using Chris Smoak's XMaps library
• Dunwich Dynamo map. Illustrates use of point markers and linear route marking based on digitizing waypoints and route in LandSerf.
• Suburban breakout. Example of Audax (long distance cycling) route shown using Google maps.
• Suburban breakout with customised labels. Example showing how overlay appearance can be customised and responsive to level of detail.
• Global shortest distances Example showing extensions that allow arcs of great circles to be drawn for globlal shortest paths.
• Global Network Example showing random global network where source, destination and line width set from XML file.

Example Applications Using Google Maps

• gmap pedometer Excellent site that allows you to digitize routes using google maps, and save the results as permalinks or GPX files.
• Chicago crimes View crime incidences along user defined route (shows two-way niteraction and integration with external databases)
• A walk in the Coniston fells (shows how GPS data can be used to create dynamic mapping)
• Where is Uz? (real-time AGPS tracking using Japanese mobile phone with embedded GPS)
• Spatially referenced sounds! (demonstrates novel spatial indexing and the embedding of multimedia within google maps)
• Exmouth to Seaton cycle ride (dynamic map panning using a GPS and SVG - see also Using SVG with Google maps).

Useful Links

• The Google maps API documentation.
• Google maps API discussion forum.
• Wiki devoted to the Google maps API.
• Google maps API v.2 tutorial and links.
• GPX format description (XML for GPS data, useful for vector overlay).
• The XMaps extension to Google Maps (useful for polygon overlay and advanced text placement).
• Some Javascript 'hacks' that allow interactivty with the Google maps API.
• LandSerf Can be used for digitizing, map projection and format conversion.