[pgrouting-users] about use of navteq data

[Charles Galpin]

Sorry for not seeing this last week. Yes Stephen was kind enough to explain his algorithm to me when I ran into this and I implemented my own versions and posted them here as well (see the archives). They are different implementations of the same algorithm (credit goes to Stephen) so they should behave the same, but all I can tell you is mine "works for me" :)  Likewise feel free to use it, and it would be nice if it made it into pgRouting.

I have not tried it since I first started looking at pgRouting, but in theory you should be able to use navteq's ref_in_id and nref_in_id  which are the equivalent of the source/target pgRouting builds itself, but I had issues (but can't recall the specifics).

charles

On Jan 21, 2011, at 11:09 AM, Stephen Woodbridge wrote:

> He may have read that I did something like this. I hacked up a version of assign_vertex where I stuffed the zlevel of the node into the z value of the coordinated, so point(x, y, zlevel) and then computed the distance_3d() or whatever the function is called in postgis when comparing the vertices. This seems to work fine.
> 
> I have attached my sql functions. Feel free to modify this and add it to pgRouting as appropriate.
> 
> -Steve
> 
> On 1/21/2011 6:24 AM, Daniel Kastl wrote:
>> 
>> 
>> 2011/1/21 Paolo Lubrano <paolo.lubrano at inwind.it
>> <mailto:paolo.lubrano at inwind.it>>
>> 
>>    Hi all, hi Charles,
>> 
>>    actually I'm working on a pgrouting graph built on TeleAtlas
>>    Multinet data.
>> 
>>    I have problems with Z level, because two streets on different
>>    levels are considered as parts of crossroad.
>> 
>>    To explane better my problem this are the data of my network table:
>> 
>> 
>>    name                             source      target
>>    Tangenziale di Napoli    402837    413133
>>    Via Giustiniano              402837    388759
>> 
>> 
>>    I built the graph with assign_vertex function, I have read about a
>>    new 3d version but I didn't found anything, where can I get it?
>> 
>> 
>> 
>> You read this about PostGIS?
>> pgRouting doesn't have a special support for 3D (Dijkstra algorithm even
>> doesn't need geometry information).
>> If you have two roads crossing each other sharing a node, but they
>> actually shouldn't be connected, because they have different z-levels,
>> then there shouldn't be shared node. Then the network topology isn't
>> correct.
>> 
>> If assign_vertex function produced this topology, then it would be good
>> to think about how to identify such a case and add z-level support to
>> assign_function. Maybe some extended assign_vertex function could check
>> if the road segments are in the same z-level.
>> 
>> Because you're using TeleAtlas data, are you sure you have to build a
>> network topology? Doesn't TeleAtlas already contain such an information?
>> If you need to run assign_vertex and your data is of good quality, you
>> could make the "snapping" tolerance parameter very very slow. But this
>> won't help if in your case both roads share exactly the same node.
>> 
>> Daniel
>> 
>> 
>> 
>> 
>>    Thank you very much!
>> 
>>    Paolo