Traffic Model

From Tygron Support Wiki
Jump to: navigation, search
Please note: This page is currently being updated.

After reading this page:

  • you've learned what a Traffic Model is.
  • you've learned how a Traffic Model relates to the Tygron Platform.
  • you've learned about the different Traffic Models in the Tygron Platform.
  • you've learned how to add a Custom Traffic Model to your project.
  • you've learned how to change the Traffic Model dynamically in your project.


What is a Traffic Model

From Wikipedia, the free encyclopedia

A traffic model is a mathematical model of real-world traffic, usually, but not restricted to, road traffic. Traffic modeling draws heavily on theoretical foundations like network theory and certain theories from physics like the kinematic wave model. The interesting quantity being modeled and measured is the traffic flow, i.e. the throughput of mobile units (e.g. vehicles) per time and transportation medium capacity (e.g. road or lane width).

How does a Traffic Model relate to the Tygron Platform?

The main purpose of the default traffic model in the Tygron Platform is to calculate the effects of traffic on the 3D World through traffic densities. In order to calculate this impact, data such as the number of traffic lanes, the traffic speed and the traffic flow on a particular lane can be added to the project. The traffic model is a static model that does not change by carrying out Actions, Upgrades or Measures for example. Read below how to create your own dynamic traffic model and use it in the Tygron Platform. The following overlays show data from/effects of the traffic model:

Traffic Data

When creating a new project a traffic model is generated for the selected project area, based on available open data sources. The following datasets are used:

Edit Traffic data

The right panel shows details about the selected road part

Height offset

This field specifies the height offset of a bridge.

Units per hour

This field specifies the number of units that can drive on a road in an hour.

Lanes

This field specifies the number of lanes that a road can have.

Noise Sigma

This field specifies the correction factor at reference traffic speed [1].
This value is used in the calculation of the Traffic Noise (Overlay).

Noise Tau

This field specifies the correction factor per 10 km/hour deviation from reference traffic speed [2].
This value is used in the calculation of the Traffic Noise (Overlay).

Speedlimit

This field specifies the max allowed speedlimit on road or part of a road.

Add a custom Traffic Model

It is also possible to creata and add a custom traffic model, better suited for your use case. The traffic model can be either a static model (the model and data do not change in the project) or a dynamic model (the model and data change when something in the 3D world changes).

Static Traffic Model

A static model does not change (over time), when changes occur in the 3D world. This type of model can be used when you for example have a scenario for 2030 ready that contains the traffic intensities then and want to use this data in your project. To upload the dataset, create a Geojson file of the data and make sure the features contain an attribute with the number of units/hour. This attribute will overwrite the current TRAFFIC_FLOW attribute of the roads. When importing this data, Constructions that are intersected by sections of the imported data are given the new traffic flow attribute of imported data.

Editor → Current Situation (Ribbon tab) → Geo import (Ribbon bar)

How to add a Static Traffic Model using the Geo Data Wizard:

  1. Select the Geo Data header
  2. Select the Geo Import bar
  3. Notice that a Geo Data Wizard window appears
  4. In the data wizard select the type 'Buildings'
  5. Select the 'Import a GeoJson file' option in step 1
  6. Select the GeoJson file you wish to add in step 1
  7. View the features of the selected GeoJson file in step 2
  8. Select the 'No Filtering' option in step 3
  9. Select the option 'Only update existing building with attributes' and the option 'Any Building' in step 4
  10. Ensure that the attribute TRAFFIC_FLOW is activated in the list of attributes in step 5
  11. Select 'Finish' in step 6


Dynamic traffic model

A dynamic model changes (over time), according to changes in the 3D world. An example of a dynamic traffic model is a model in where is calculated how the traffic intensity changes when building a certain amount of houses. Effectively the TRAFFIC_FLOW attribute of the roads will be updated with a new value, when building houses in the Tygron Platform. To create such a model, first create a Geojson file with the roads that will be changed by a certain Action or Measure and import the file. In an Excel file, the calculation for how much and when the traffic intensity changes has to be made. This file can be uploaded as either an indicator or panel. The indicator or panel explanation text in this case is not relevant. The Excel is only used to define the model and import it in the Tygron Platform.

Example excel Traffic Flow panel template




The Excel implementation of a simple dynamic traffic model, consists of the following consecutive steps:

  • Retrieval of the original traffic density in Area X - SELECT_ATTRIBUTE_WHERE_NAME_IS_TRAFFIC_FLOW_AND_AREA_IS_X


  • Calculation in an excel file, with the new traffic density as outcome - original traffic density + change


  • Output of the new traffic density for constructions in Area X - UPDATE_BUILDING_TRAFFIC_FLOW_WHERE_AREA_IS_X


Editor → Current Situation (Ribbon tab) → Geo import (Ribbon bar)

How to add a Dynamic Custom Traffic Model using the Geo Data Wizard:

  1. Select the Geo Data header
  2. Select the Geo Import bar
  3. Notice that a Geo Data Wizard window appears
  4. Select the type 'Areas' in the Geo Data Wizard
  5. Select the 'Import a GeoJson file' option in step 1
  6. Select the GeoJson file you wish to add in step 1
  7. View the features of the selected GeoJson file in step 2
  8. Select the 'No Filtering' option in step 3
  9. Select 'Import a New Area with attributes' in step 4
  10. Select an option on how you want to name the features in step 5
  11. Ensure that the attribute TRAFFIC_FLOW is activated in the list of attributes in step 6
  12. Select 'Finish' in step 7



How to add an Excel Indicator or Panel:

  1. Select the Indicators header
  2. Select the Indicators bar or Panels bar depending on what is needed
  3. Select the type 'Add Excel Indicator' option or 'Add Excel Panel' in the dropdown menu
  4. Select 'Select Excelsheet' in the right panel
  5. Select 'Import New Excelsheet' in the popup window
  6. Choose an excelsheet and select 'Apply'
  7. Rename the added indicator in the 'Name' and 'Short Name' fields on the right panel
  8. Select the color to be used in the progression panel
  9. Select to activate the indicator, if desired
  10. Add a proper description
  11. Highlight 'Excel File Name' on the left panel
  12. Select the 'Upload' button
  13. Select the file to upload in the 'Choose your file' panel
  14. Select Indicators > recalculate Indicators


Create GeoJSON File


How to create a GeoJson file in QGis:

  1. Open QGis
  2. Select the Layer tab
  3. Select 'Add Layer' in the Layer tab
  4. Select 'Add Vector Layer' in the dropdown menu
  5. Choose the file you wish to add and select 'Open'
  6. Notice that the file appeared in the Layers Panel
  7. Select the newly added file and choose 'Save As'
  8. Notice that a new window with options has appeared
  9. In the 'Format' field choose 'GeoJSON'
  10. In the 'Name' field enter a name for the file
  11. In the 'CRS' field choose the right CRS for the file
  12. Select 'Ok' to create and save the GeoJSON file
  13. Notice that the newly created GeoJSON file is added in the Layers Panel