Isochrone Tool

The isochrone tool is used to visualise the spatial accessibility provided by your multi-modal transports networks.

Isochrones Overview

Isochrones depict areas on a map accessible from a certain point within equal travel times. Isochrones in Podaris can be one of two kinds:

  • Travel time - this type of isochrone calculates the accessibility to or from one or more locations on a given day at a given time. When combined with datasets through queries, you can answer questions such as:
    • “How many residents can access hospitals within 15, 30, 45mins through the public transport network?”
    • “How many jobs are accessible from this housing development at 9 am on a Monday?”
  • Access time - these can be used to analyse the catchment of a route, sets of stations, or cycling infrastructure. Access time isochrones can help you answer questions like:
    • “How many people live within 10 mins of stops along a bus route?”
    • “What is the average income of people who live within the catchment of bus stops in Belfast?”
    • “How many schoolchildren can access a bus stop within 5 mins of walking?”

Using Isochrones

The number and size of the steps are configurable through the Tool Properties panel. Station-to-station travel times are calculated per the Station matrix, while radiuses around the station assume a standard walking speed (crow-flies distance).

Note that for stations to be accessible to the isochrone, they must be connected to and reachable through the network.

Isochrone tool properties

isochrone tool properties

Recalculate Update isochrone after changing a property
Export Export isochrone as GeoJSON, shapefile or KML
Save

Save current isochrone. Saved isochrones can be recalled and operated on in a variety ways from the isochrone tool panel.

Saved Isochrones

Saved isochrones can be selected from the isochrone tool panel - clicking the name of a saved isochrone other than the one that you are viewing, will restore it.

Clicking on the name of the currently active isochrone will dismiss that isochrone. The add icon button has the same effect, and creates a new, unsaved isochrone.

add icon Create a new isochrone.
download

Download selected isochrone as either:

  • Geometry (polygons for the isochrone geometry as GeoJSON, Shapefile or KML)
  • Query Results (a .CSV containing results of all queries for this isochrone)
duplicate Duplicate saved isochrone
delete Delete saved isochrone

Travel Time Isochrone Properties

Travel Time Isochrones

Type From/To as set by the departure/arrival times respectively
Location
  • Point: as selected by clicking a location on the map
  • Set location according to an isochrone query This offers the possibility of creating multi-point isochrones by creating a query that selects entities within an imported dataset, for example.
Mode Car/Cycle/Transit/Walk.
Day Day of the week, taking into account services running in your project.
Depart/Arrive at (Impacted by From/To type, respectively). Time of that day.
Access Profile
  • Walking (crow-flies: 2.5mph/street-based: 3mph)
  • Cycling (crow-flies: 13mph/street-based: see below*)
  • Other access profiles are available on request through support.
Origin Steps When enabled, this will also show concentric origin steps from the exact location of the 'isochrone man' as it is positioned on your map (as opposed to steps from connected stops across infrastructure)
Max Access Distance Set a limit on the maximum walking/cycling access distance
Transfer Limit Set a limit on the maximum number of transfers that can be made

* For the street-based cycle isochrone we account for speed changes as a result of underlying elevation and road type-specific speed restrictions, however, the default speed for a flat normal road is 13mph.

Drive time isochrones using the car profile are currently in public beta. Unlike journey's found through bus planning or the simulation engine, these do not take into account historical data by default. Instead, they assume free-flow speeds using the posted maximums.

Access Time Isochrone Properties

Type
Depart at Departure time, set by a 24 hour clock, that takes into account services running in your project.
Access Profile
  • Walking (crow-flies: 2.5mph/street-based: 3mph)
  • Cycling (crow-flies: 13mph/street-based: see below*)
  • Other access profiles are available on request through support.

* For the street-based cycle isochrone we account for speed changes as a result of underlying elevation and road type-specific speed restrictions, however, the default speed for a flat normal road is 13mph.

Step and Styling Properties

Step Size Isochrone step size in minutes
Steps Number of steps
Color Color scheme
Opacity Isochrone opacity

Styling properties allow for isochrones to be rendered in many different ways:

isochrone-settings

Changing tool will automatically clear and remove any isochrones which have not been pinned to your current view.

Pinned isochrones

Isochrones can be pinned to specific Views, allowing them to be shared with others -- including stakeholders using Podaris:Engage -- as well as captured in snapshots.

When creating a new view, the currently active isochrone will be pinned to that view. Note that if you make any changes to the location or properties of an isochrone while it is pinned, these changes will be saved to the view.

Views with pinned isochrones are indicated by the presence of an "isochrone man" icon on its entry in the Views panel.

view-with-pinned-isochrone