1.
Using network segments in the
spatial representation of travel
time isochrones

2.
Isochrones
Iso = Equal Chrone = Time

3.
https://upload.wikimedia.org/wikipedia/commons/8/86/Isochronic_Passage_Chart_Francis_Galton_1881.jpg

4.
https://archive.org/details/atlasofcommercia00bart

5.
https://en.wikipedia.org/wiki/File:Map_of_Melbourne_and_environs_minimum_railway_or_tramway_time_zones.jpg

6.
https://en.wikipedia.org/wiki/File:Map_of_Melbourne_and_environs_minimum_railway_or_tramway_time_zones.jpg

7.
Existing Tools:
ArcGIS Network Analysis
PostGIS + pgRouting
OpenTripPlanner
Dozens of Web Applications
etc.
General Steps
1 - Create a Network Graph
2 - Compute travel time from a
point to network vertices
3 - Generate shapes or surface
for specific travel times
4 - Visualize output
Output:
Isolines, polygons, vector
grids, or rasters that
represent the AREA that is
accessible from a point (or
points)

8.
A structural alternative:
General Steps
1 - Create a network graph
2 - Compute travel times from a
point to network vertices
3 - Generate shapes at specific
travel times
3 - Join travel times to edges
4 - Classify / visualize output
Using network segments in the
spatial representation of
travel time isochrones.

9.
Output Data Structure:

10.
Questions
1 - How can this technique be applied?
2 - How can it lead to new insights about our data?
3 - When is it preferable over conventional isochrones?
or

11.
1 - Mapping Differences in Travel Times:
By Travel Mode
By Time of Day
For Different Transit Agencies

12.
1 - Differences in Travel Times

13.
1 - Differences in Travel Times

14.
v 2 - Combining with Areal Data

15.
3 - Potential Path Areas

16.
4 - Transit Maps:

17.
4 - Transit Maps:

18.
4 - Transit Maps:

19.
5 - Travel Surveys:

20.
5 - Travel Surveys:

21.
5 - Travel Surveys:

22.
Some code & maps are on my github page at jamaps.github.io
Thank You!