geocoding, book referrals. was: [Gpsbabel-misc] OT, Data vs Maps

[Robert L. <rob...@us...>]

I'm reluctant to play along with an OT discussion, but I'll turn this
back into a plug for our own (and related literature) in a moment...


> >> http://geocoder.us/ <<
> >> http://developer.yahoo.net/maps/rest/V1/geocode.html <<
> 
> Thanks!
> 
> Both look like great resources... although the us census data from 
> geocoder got the city wrong on my address ;-)

Geocoding is hard.  The reality is that collecting coordinates for every
mailbox in even a small country would be crazy expensive.  So what
typically happens in most data sets (including Tiger and Navteq) is that
the road segments get address ranges.  There are size and cost tradeoffs
in picking the size of those ranges.  Typically an address range will
span several blocks.  The result of all this is that a program has
available the coords of the end points of a road segment and that road
segment is named "Maple street" and that it contains "odd addresses
1001-1399 on the north and even 1000-1398 on the south".  If you're
in an area that has houses exactly evenly apart and doesn't have an
apartment or a park in there, it usually works well enough that you can
drive to the extrapolated coords and start looking without thinking too
much about it.  Sometimes you'll be a couple of blocks off.

The first resource above is provided by Locative Technologies.  Their
principles are Rich Gibson and Schuyler Erle.  Those happen to be
two of the three authors of Mapping Hacks.  See the book link at
	http://mappinghacks.com/ 
and the TOC at 
	http://www.oreilly.com/catalog/mappinghks/index.html .
It contains sections on geocoding and many other topics that may be of
interest to this crowd.   It's really a nice introduction to electronic
mapping and provides nice definitions and example of various projections,
software, and techniques.  It also contains several hacks that mention,
use, or are predicated upon GPSBabel.  (My favorite byte is at the bottom 
of page 226, "As befits a Swiss Army Chainsaw, GPSBabel has...")


Within the next month or two, we'll see another book by that duo:
	http://www.oreilly.com/catalog/googlemapshks/
It, too, is likely to be found useful by the kinds of people that 
use GPSBabel - especially if you use Google Maps, of course.    It
has a couple of sections written by Ron Parker and myself.  The final
TOC for that one hasn't made it ot the site yet, but if you're a user
of Google Maps or a developer, you're likely to find new rabbits to put
in your hat.

Sarbanes Oxley disclaimer:  I get paid the same whether you buy the
book or not. :-)

RJL