[Geodata] Ok, I'm here . . . (Tiger stuff.)

Bob Basques bob.b at gritechnologies.com
Sat Jun 21 19:58:42 EDT 2008


Stephen,

Stephen Woodbridge wrote:
> Bob Basques wrote:
>> Stephen,
>>
>> I'm using the Tiger data mainly for mapping right now, I'm interested
>> in the addressing side as well, but have a good local dataset for
>> this, also looking at OpenStreetmap for some comparable value.
>
> I would be interested in this also, but I'm stack overflow at the 
> moment so that will have to wait.
We have the OpenStreetmap database (whole world) installed in POSTGIS 
already, took a few days to just run the index, anyway, it works, and 
pretty darn quick, we're not POSTGIS gurus (yet) though, so I'm sure 
there is more tuning to be had in the response times
>
>> My main interest, and problem area, at the moment with the tiger data
>> is the road classification stuff,  It seems overly complicated, but I
>> don't know all the subtleties related to who uses what and how.  I've
>> been trying to apply the Googlish looking MAP file to it, and it's
>> been an uphill battle.
>
> Yes, well I have two major issues in this area.
>
> 1) CFCC to MTFCC change lost a lot of information about the segments 
> as it appears to be a courser gain resolution and it seems to be way 
> more complicated. I guess we will have to learn to live with this change.
>
> 2) When you compare Tiger to Google (Navteq or TeleAtlas) the later 
> have a major road classification that is not present in the Tiger 
> data. These roads are classified as CFCC=A4* in the old data. 
> Basically the missing classification in tiger would allow you to 
> identify the roads in light yellow on this google map:
Yup, this was the first think that I had a problem with.  BTW, I think 
Google is using and Average Daily Traffic(ADT)  for their map themesand 
not strictly a classification system.  My suspicion was raised when I 
noticed some local streets not theming correctly when compared to 
Google.  I have no way of know for sure though.

Do you know of any ADT datasets?   I can't figure out how google would 
be able to get this type of info, so that's why it's just a suspicion 
right now.
>
> http://maps.google.com/maps?hl=en&ie=UTF8&ll=42.163403,-88.066406&spn=2.585418,2.828979&z=8 
>
> http://maps.google.com/maps?hl=en&ie=UTF8&ll=42.163403,-88.066406&spn=0.161596,0.176811&z=12 
>
>
>> I need to come up with a dataset that will extend the coverage area
>> beyond our local dataset for centerline prorated geocoding purposes.
>
> So what are you using for a geocoding engine?
Some recent extensions to PAGC were developed here under a MetroGIS 
contract.   The Engine seems very fast. we're in the testing stages now 
with the first extended version.  I believe it will be going public on 
the PAGC list fairly soon.
> Have you create a tools for processing the Tiger data into shapefiles 
> for mapserver?
Yes, but not the new stuff, although that wouldn't be hard to replicate, 
we're using mainly PostGIS now.
>
> Stephen Frost posted a script on the postGIS list for loading the 
> Tiger data into PostGIS which can be found here: 
> http://snowman.net/tiger/
We wrote our own in Python.

bobb

>
> -Steve
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