Podaris:Insight Corridor Frequency Difference Analysis

What is Podaris:Insight?

Podaris:Insight is a toolkit for simplifying a number of types of accessibility analysis. It is designed to dramatically speed up the process of performing accessibility analysis on networks and datasets created or imported in Podaris. It provides a simple interface through which analysis projects can be created and shared, and the corresponding results exported. You can learn more about Podaris:Insight and the analysis types that it offers here.

What is Corridor Frequency Difference Analysis?

Corridor Frequency Difference analysis compares the service frequency of two network scenarios — a baseline and a comparison — segment by segment across your network. Rather than running two separate Corridor Frequency analyses and comparing results manually, this analysis calculates the frequency metrics for both networks and then computes the difference for every segment:

• Positive values — segments where the comparison network has higher frequency than the baseline (shown in green)
• Negative values — segments where the comparison network has lower frequency than the baseline (shown in red)
• Zero — segments where frequency is unchanged between the two networks (shown in yellow)

This makes it straightforward to answer questions such as "which corridors benefit from our proposed timetable changes?" or "how does the restructured network affect service levels across the existing route network?".

Setting up the analysis

1. Networks to compare

Select a baseline network — the existing or do-nothing scenario — and a comparison network — the proposed or do-something scenario. Both networks can come from any project in your workspace.

Note: Only active scheduled bus routes are included in the analysis. Both networks must already exist in Podaris before you run this analysis. If you have a proposed route change, create it as a separate network first, then select it as the comparison.

2. Baseline time period

Define the time window for the baseline network. Frequency is calculated based on the number of trips on each segment within this window.

• Day — the day of the week to analyse (e.g. Monday)
• Start time — the beginning of the analysis period (e.g. 07:00)
• End time — the end of the analysis period (e.g. 09:00)

3. Comparison time period

By default, the comparison network uses the same time period as the baseline. Leave Use same settings as above? set to Yes to compare like-for-like — for example, both networks during Monday morning peak.

Set it to No if you need to compare the baseline at one time period against the comparison at a different one — for example, to assess whether a proposed evening service matches the existing morning peak.

Interpreting results

The results map displays your network coloured according to the difference in frequency between the two scenarios. The default attribute is Avg VPH Diff (difference in average vehicles per hour, calculated as comparison minus baseline), using a red-yellow-green diverging colour scale.

Clicking a segment on the map shows the full set of statistics for that segment, including:

You can change the displayed attribute at any time using the Attribute dropdown in the display settings panel. The colour classes can be adjusted by dragging the class boundaries on the slider or editing them in the class settings below the map.

Exporting results

Your analysis can be exported by clicking the project name and selecting Export Analyse. Corridor Frequency Difference exports as a GIS file (GeoJSON) containing one feature per network segment, with all difference and per-scenario frequency attributes attached as properties. This can be opened in GIS software such as QGIS to apply your own styling or perform further analysis.