[postgis-users] dynamic segmentation

[Stephen Woodbridge]

P Kishor wrote:
> On 11/16/06, Stephen Woodbridge <woodbri at swoodbridge.com> wrote:
>> P Kishor wrote:
>> > Someone asked me recently about open source dynamic segmentation
>> > solutions. I thought, let's ask the PostGIS community. Is this
>> > possible with PostGIS? If not, does anyone know of other open source
>> > solutions for ds?
>> >
>>
>> Can you describe what dynamic segmentation is?
>> What is the algorithm?
>> I guess I can google for it ...
>>
> 
> I don't know the algorithm, but among the many definitions, dynamic
> segmentation allows analysis and mapping of linear features based on
> their positions along a route. Another definition says that it is "the
> process of computing the locations of events on linear features at run
> time based on event tables for which distance measures are available."
> Used in linear reference systems (LRS), typically for roads and
> transportation networks analysis.
> 
Ok, well google has a bunch. It seems that you need to have a route 
first, then dynamic segmentation just means you can reference a point 
along the route based on distance or cost to get to that point.

For geocoding, a house is some percent of the distance along a segment.

So I guess the question is, what are you asking for? A routing engine, 
check out pg_dijkstra, I'm not sure if it has the ability to do dynamic 
segmentation.

In a simpler view, if you have the sum of the segments lengths along a 
path, and the percentage along the first and the last segment, then you 
have dynamic segmentation.

-Steve