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
Matthew,
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.
-Steve
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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