Hasn't anyone else ever built anything like this ? Was Google really
first in doing this ?
By no means. Web Mapping is a mature and active topic in Geographic
Information Systems, and there are very active standards bodies out
there - Open Geospatial Consortium (OGC) on the industry side and ISO
TC211 on the formal standards side. There are quite a few similar
services to Google maps out there - look at
www.multimap.co.uk, for
one, where advertizing is linked to a map. This is in principle little
different to Google maps, and it has ben around for years! I am
currently working on implementing a web Map Server and Web Feature
Server for Antarctica, using stable, well established open-source
toolkits to do so (Geoserver and PostGIS for those interested).
Google's new slant is to link mapping to their query engines.
However, this has little or nothing to do with Javascript - the volume
of data required to make anything work means that almost all the
intelligence is in the back-end on the server. I will be doing a
little Javascript development to portray map data over the next month
or so, but this is simply to allow a simple user interface to
construct complex URLs that are submitted to a server.
SVG is, of course, a popular portrayal mechanism for map data, but map
data are more complex "under the hood" and SVG is not suitable for the
back-end storage and manipulation of map data.
Paul