Heatmap - Connectivity

The Heatmap - Connectivity indicator produces a color-coded map to visualize the connectivity of locations within an area of interest (AOIGlossaryArea of interest (AOI)The geographic area an analysis covers, defined by a boundary, everything outside which is excluded from the result.Read more ↗).

1. Explanation

The heatmapGlossaryHeatmapA map that shows a computed value across a continuous surface using colour, rather than symbols at individual locations.Read more ↗ uses a color-coded hexagonal grid to show how well-connected different areas are. It takes an Area of Interest (AOI), a routing type (walking, cycling, etc.), and a travel time limit as inputs. Considering real-world transport and street networks, it calculates the connectivity of each hexagon within the AOI.

info

Heatmap computation is available across over 30 European countries for Walk, Bicycle, Pedelec, and Car. For Public Transport, Germany, Switzerland, and the Haut-Rhin region of France are supported. If you need analyses beyond these regions, you can import your own routing network or contact us and we will do it for you.

2. Example use cases

• Does the existing transport network provide equitable access across the AOI?
• How well connected is the street, footpath, or cycle lane network in a specific area?
• How do locations within an AOI compare in terms of connectivity across the different modes of transport?
• Are there barriers, gaps, or islands within the street network that hinder connectivity?

3. How to use the indicator?

1

Click on Toolbox .

2

Under the Accessibility Indicators menu, click on Heatmap Connectivity.

Routing & Configuration

3

Pick the Transport mode you would like to use for the heatmap.

Mode	Considers
Walk	All paths accessible by foot
Bicycle	All paths accessible by bicycle (taking into account surface and slope)
Pedelec	All paths accessible by pedelec (taking into account surface and slope)
Car	All paths accessible by car (taking into account speed limits and one-way restrictions)
Public Transport	All journeys possible by public transport (according to official GTFSGlossaryGTFSAn open standard for publishing public transport timetables, stops and routes as a set of text files, so any software can read the same data.Read more ↗ schedules), considering walking access and egress to and from stops

4

Set how travel is measured and the cost limit. The options depend on the Transport mode you picked in step 3:

Walk / Bicycle / Pedelec / Car

In the Calculate by menu, choose either the Time (minutes) or Distance (metres) cost type.

Enter a cost Limit in minutes or metres for your heatmap. This will be used according to your previously selected transport mode and cost type.

Public Transport (PT)

Choose PT modes to analyze: Bus, Tram, Rail, Subway, Ferry, Cable Car, Gondola, and/or Funicular. Then, select the Day and Arrival time for the analysis. The best public transport journeys that reach the opportunities at or before this time will be considered.

Enter a cost Limit in minutes for your heatmap.

Hint

Need help choosing a suitable travel time limit for various common amenities? The "Standort-Werkzeug" of the City of Chemnitz can provide helpful guidance.

Advanced options

Optionally, enable Advanced options to configure additional settings for routing and heatmap generation.

5

Configure various routing options for your selected transport mode such as travel speed, max transfers, access/egress limits and more. Further information about mode-specific options can be found under the Routing section.

Reference layer

6

Select the Reference layer (layer containing your area of interest) for which you would like to calculate the heatmap. This can be any polygon feature layer.

Result layer

7

Set the Result layer name for the output heatmap layer.

8

Click Run to start the calculation of the heatmap.

Results

Once the calculation is complete, a result layer will be added to the map. This Heatmap Connectivity layer will contain your color-coded heatmap. Clicking on any of the heatmap's hexagonal cells will reveal the computed connectivity value for this cell.

Tip

Want to style your heatmaps and create nice-looking maps? See Styling.

4. Technical details

Calculation

For each hexagon in the grid within the Area of Interest (AOI), the tool identifies all surrounding hexagons that can reach it. These surrounding hexagons can be outside the AOI but must be within the specified travel time and using the chosen travel method.

Connectivity formula:

The connectivity formula calculates the total area (in square meters) from which a destination cell within the Area of Interest (AOI) can be reached. It does this by considering the number of cells that can reach the destination cell within each travel time step i up to the specified travel time limit n. The sum of all these reachable areas gives the final connectivity value for that cell.

Grid cells

Heatmaps in GOAT utilize Uber's H3 grid-basedGlossaryH3 gridA system that divides the earth's surface into hexagonal cells at several resolutions, used to compute and display values over an area.Read more ↗ solution for efficient computation and easy-to-understand visualization. Behind the scenes, accessibility is computed on-the-fly by GOAT's own routing engine. For each routing type, the engine routes outward from the opportunities to discover the reachable H3 cells and their travel costs, then aggregates these into a per-cell accessibility score. Public transport uses the RAPTOR-based engine, while the active mobilityGlossaryActive mobilityGetting around under your own power, mainly walking and cycling, including pedelecs, wheelchairs and scooters.Read more ↗ and car modes use GOAT's Dijkstra implementation.

The resolution and dimensions of the hexagonal grid used depend on the selected routing type:

Mode	Resolution	Average hexagon area	Average hexagon edge length
Walk	10	11,285.6 m²	65.9 m
Bicycle	9	78,999.4 m²	174.4 m
Pedelec	9	78,999.4 m²	174.4 m
Car	8	552,995.7 m²	461.4 m
Public Transport	9	78,999.4 m²	174.4 m

Hint

For further insights into the Routing algorithm, visit Routing. In addition, you can check this Publication.

Visualization

For visualization, the result form the connectivity analysis, uses a classification method based on quantilesGlossaryQuantile classificationA way to group data into classes for a map so that each class holds the same number of features, whatever the range of values inside it.Read more ↗ by default. However, various other classification methods may be used instead. Read more in the Data Classification Methods section of the Attribute-based Styling page.