Using network segments in the

spatial representation of travel

time isochrones

Isochrones

Iso = Equal Chrone = Time

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

https://archive.org/details/atlasofcommercia00bart

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

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

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)

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.

Output Data Structure:

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

1 - Mapping Differences in Travel Times:

By Travel Mode

By Time of Day

For Different Transit Agencies

1 - Differences in Travel Times

1 - Differences in Travel Times

v 2 - Combining with Areal Data

3 - Potential Path Areas

4 - Transit Maps:

4 - Transit Maps:

4 - Transit Maps:

5 - Travel Surveys:

5 - Travel Surveys:

5 - Travel Surveys:

Some code & maps are on my github page at jamaps.github.io

Thank You!