[pgrouting-users] Implementation of Driving Distance Function

Stephen Woodbridge woodbri at swoodbridge.com
Mon Aug 18 10:22:41 PDT 2014


You probably want to look at the distance matrix tools, this allow you 
to enter a number of locations and computes a matrix of all costs to get 
from any node to any other node.

I also believe I wrote some code (it might be in the current develop 
branch in github that does one to many routes, ie computest the cost 
from one node to a list of other nodes.

We also have a driving distance function that allow you to set a start 
point and then can generate isograph polygons of equal cost from the 
start node expanding outward.


On 8/18/2014 12:53 PM, Matthew Baker wrote:
> Hi all,
> During the day I wear my Denver Public Schools hat, and have been
> spreading the good word of SQL Spatial, specifically ST_Distance, to our
> analysts here with much relief and excitement. They are database users,
> not "GIS" users, so the ability to simply add a distance query to their
> existing (and complex) enterprise queries brings huge power to our
> analysis, and of course is very intuitive.
> Additionally, I've been spreading the word of the concept of
> /'/distance/along the network'/ (ie. driving distance or pgr_kDijkstra
> algorithms in pgRouting) as they apply to routing kids to their closest
> school by program type, grade, etc... which brings an equal or greater
> level of excitement from our analysts...
> Distance along a network as a SQL spatial function has huge potential in
> the way we assign kids to a school, as the system of polygon
> 'boundaries' is becoming more and more scrutinized as a solution whose
> time has almost come to an end.
> My question is - and see the recent posts below on GIS.SE on this
> subject - *how can the driving distance functions be implemented in the
> same way that ST_Distance works*... ie, I have a table of points
> (student households), and 2nd a list of points (schools), and want to
> determine the students closest school (including other attribute filters
> such as program type, etc.).
> GIS.SE / recent questions:
> http://gis.stackexchange.com/questions/110716/nearest-facility-with-pgrouting
> http://gis.stackexchange.com/questions/110838/how-to-calculate-the-shortest-distance-for-multiple-source-and-targets-using-pgr
> Many thanks for any insight / thoughts / suggestions!
> -m
> Matthew Baker
> Denver Public Schools
> Department of Planning and Analysis
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