Wednesday, March 16, 2011

Coming Down the Pipe: Drive-Time Coverage!

Folks in shipping, planning, or logistics spend a considerable amount of time wondering, "how far can I get in a certain amount of time?"  It's our goal to answer that question, and trim down the amount of time used in the asking.  Plus drive-time looks pretty cool, and cool looking stuff is another goal.
IDV's algorithmically inclined Abhinav Dayal created the service and took great care to balance speed and precision.  Here are some screenshots from the testbed...

5 incremental drive-time rings of 5 miles each, starting from my house.  Looks right! 

10 rings from downtown San Francisco, I don't remember the time spacing.

Some drive-time areas from Manhattan...

...and some more around Baltimore.

The workflow
With a service like this, it is a good idea to have sufficient points of entry to accommodate foreseeable workflows.  Below, for instance, is a storyboard describing a generic activation from tools workflow.  But you might also want to right-click on an ad-hoc location on the map or use an existing feature as the origin point.

Sequence-heavy feature planning benefits from a comic strip.  This storyboard describes one of the access methods to the drive-time service.

Some Interesting Notions
Traffic Multiplier
Drive-time polygons are only useful if they bear some semblance to reality, and a clear gotcha for anyone behind the wheel is traffic variability.  Allowing the user to define a generic offset to the expected speed is a simple way to calibrate these doodads.  The inclusion of a real-time service of actual traffic conditions is a clear enhancement, not without its own trade offs.
Quick Change
Changing the location of the drive-time origin and time slices should be easy and natural.  This means clicking and dragging to new locations and modifying the number of rings, and their timing in a simple interface.  Or something.
Inputs to other Workflows
A drive-time polygon is pretty interesting for interesting's sake.  But it's also a useful input for a spatial query.  'How many whatevers are within a certain driving time?'

Anyways, things are coming together and I'll keep you posted on this and other doodads as they cook.

1 comment:

  1. Hi John,
    This is along the lines of an alternative functionality request I made #2 here:

    Though my request suggests it as tool on a details panel for an individual feature to be buffered, an additional "Analysis" tool could be built alongside the traffic tool you describe in your storyboard:

    Storyboard step 1: User selects the "Spatial Analysis" tool (with little sub-tools like the existing spatial query tool has) one of which is "drive time", one is "buffer". The flow proceeds as you describe with the modal dialog just presenting buffer distance and distance units, as opposed to drive times. You guys already have the algorithm for buffering so you could just simply tap into that to generate the simple buffer, a highly requested feature by our more GIS savy clients. Again the workflow progresses as you describe allowing the user to use the buffer to spatially select other features... sounds like a straightforward enhancement to me! Hope you guys can include it.