[pgrouting-users] Assign Vertex ID time

[Ian]

On 6/1/12 1:21 PM, Stephen Woodbridge wrote:
> On 6/1/2012 11:45 AM, Ian wrote:
>> Hi all,
>>
>> Does anyone have any estimations on how long it would take to run
>> assign_vertex_id on the entire Census TIGER dataset for the United 
>> States?
>> Say you had a 2.6ghz intel core 2 duo processor and 8gb of RAM? Or has
>> anybody done this and have a time and their computer's specs?
>
> I'm going to take a wild guess that it is something in the ball park 
> of 1 week. You have a secondary problem in that this is all done in a 
> single stored procedure call, which means that it is all done in a 
> single transaction. This might be an issue as the transaction will 
> become extremely large.
>
> You might look at using the TNIDF and TNIDT which are the Tiger assign 
> node numbers.
>
> So how are you planning on using this data with pgRouting? Tiger does 
> not have attributes like oneway streets, zlevels at intersections or 
> turn restrictions all of which are needed to do useful routing planning.
>
> Are you aware the using tiger you will generate routes like enter an 
> exit of highway, drive to the top of an overpas and make a left hand 
> turn onto the underpass 20 feet below you, etc?
>
> It can be useful for some restricted routing uses where you can 
> overlook these issues but in general it is not suitable for most 
> routing tasks.
>
> -Steve
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Thanks for the input.

So TNIDF & TNIDT can be imported to the 'source' & 'target' columns as 
long as they are properly linked to the endpoint geometry?

My project has to do with walking in cities so I'm thinking that I will 
be able to overlook routing issues associated with driving....I will 
have to make some assumptions though (sidewalks ped-xings), but streets 
in cities tend to be walkable.

I noticed that OSM data has some attribution TIGER data does not, maybe 
I should look there too.

Even if I clip the streets to only include the areas I really need 
(cities with a population of over 10,000), I'm guessing that would still 
be the majority of all the streets (maybe 1/3 or more?)

Well... if I end up doing assign_vertex_id on a large dataset I'll 
report back any useful results,

ian