Re: geocoding

Mark Bucciarelli wrote:
>
> If you are limited to the US, you can use the Tiger files supplied
> by the U.S. Census. Each line segment has fields like primary name,
> secondary name, starting address left, starting address right, ending
> address left, ending address right. You can generate the lat/long
> by finding the segment by matching the street name, and then
> extrapolating to match the street number.
>
> I think one reason companies can charge thousands of dollars is that
> the accuracy of the Tiger files is not great. In particular, there
> are errors with street names and some (many?) of the newer streets
> won't be there at all.
>
> It would be interesting to see a comparison of hit rates. If the
> vendors don't provide one, then maybe the Tiger files aren't so bad
> after all ... ;)
>
> Also, I think there is an initiative by Galdos, Inc. to provide the
> latest Tiger files in GML format, which should be interesting.

It's actually the US Census Bureau that's doing this (with Galdos as a
contractor). http://www.gmlcentral.com/tiger/ has a Tiger/Line to GML
translator they built.

You may also want to look at the Geocoder spec under development at
the OGC. If you do build a geocoder, you could use the interfaces in
the spec and be ready to either run a geocoding service or you would
be able to plug in a commercial version without having to change your
code. MapInfo has been strong in that area. Look at the fifth entry in
http://www.opengis.org/techno/discussions.htm (look for document
01-026r1)

        Allan

>
> --
> Mark Bucciarelli Peregrine Systems, Inc. R&D, Boston
> (413) 253-0020 mbucciarelli@peregrine.com Yahoo: m_bucciarelli
> http://www.peregrine.com
>
> > -----Original Message-----
> > From: Nate Tanner [mailto:Nate.Tanner@knowledgenet.com]
> > Sent: Tuesday, July 03, 2001 3:57 AM
> > To: 'openmap-users@bbn.com'
> > Subject: geocoding
> >
> >
> > Hi ya'll,
> > I am working on a little project, not using openmap at this
> > point, but I
> > figured this was the right crowd for this question. For part
> > of the project
> > I basically want someone to come to a web page, enter their
> > address or major
> > cross streets, and hit submit. Then I want the server to geocode the
> > location and return the latitude and longitude.
> > I've seen some commercial products that cost thousands of
> > dollars that will
> > do this sort of thing, but I figure there's got to be some inexpensive
> > options, even if I have to do a little data manipulation
> > myself. Where can
> > ya point me?
> > Thanks in advance for any help,
> > Nate Tanner
> > -----Original Message-----
> > From: Ken Anderson [mailto:kanderson@bbn.com]
> > Sent: Friday, June 29, 2001 7:46 PM
> > To: Tennessee Leeuwenburg; openmap-users@bbn.com
> > Cc: rshapiro@bbn.com
> > Subject: Re: printing
> > I'm not an openmap developer, and I haven't printed myself,
> > but Rich Shapiro
> > has. I think getting transformations and clipping right can
> > be tricky. Maybe
> > sending us your code or trying random algorithms might help.
> > k
> > At 01:13 AM 6/29/2001, Tennessee Leeuwenburg wrote:
> > >Hi all,
> > >
> > >I've implemented printing in Openmap, but I have one
> > persistent problem.
> > The image I get has (obviously) the same dimensions as the
> > map. In my case,
> > those dimensions aren't the same aspect ratio, and are larger
> > than, what
> > will fit on the printable area of an a4 page. This results in
> > clipping. I've
> > found that rescaling the image will rescale my printed output, but not
> > actually change where the image is being clipped. (i.e. my
> > output changes
> > size/ratio, but only the clipped output appear, even though
> > the new size
> > would be large enough to accommodate the entire image. Any
> > ideas anyone?
> > >
> > >-Tennessee
> > >==============================================
> > >This email contains information which may be useful. The views
> > >expressed within may or may not be the views of the author.
> > >==============================================
> > >
> > >-Tennessee Leeuwenburg, Silver Stream Pty Ltd
> > >0418 300 881
> > >
> > >--
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-- 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Allan Doyle                     adoyle@intl-interfaces.com
International Interfaces        +1 781 433 2695 (Office)
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