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Extract Roadway Geometry Command

The Extract Roadway Geometry command allows the user to extract high chord geometry and internal bridge geometry of roadway crossings from digital terrain layers. Additionally, for 2D roadway crossings, the user can extract the elevation data from approach and exit cross sections. The extracted geometry data will automatically get populated in the appropriate fields of the bridge and culvert data dialog boxes.

Note that 1D roadway crossing geometry data will get populated into the Bridge & Culvert Data dialog box, whereas 2D roadway crossing geometry data will get populated into the 2D Bridge & Culvert Data dialog box.

Refer to the below articles in our knowledge base to learn more about 1D and 2D bridge modeling:

Follow the steps below to use the Extract Roadway Geometry command:

  1. From the Input ribbon menu, click the Roadway Crossings dropdown menu and then select the Extract Roadway Geometry command.
    Extract Roadway Geometry ribbon menu command
  2. The Extract Roadway Geometry dialog box will be displayed.
    Extract Roadway Geometry dialog box

Note that this command is also available in the roadway crossing right-click context menu.

The following sections describe the Extract Roadway Geometry command and how to interact with the above dialog box.

Selecting Roadway Crossing

The Select Roadway Crossing section allows the user to select the roadway crossing in order to extract the roadway geometry. It contains two panels:

  • 1D Roadway Crossing
  • 2D Roadway Crossing

The Extract Roadway Crossing dialog box will default to either the 1D or 2D Roadway Crossing panel based on the following criteria:

  • If the user has only 1D elements in the model, the 1D Roadway Crossing panel will be displayed by default.
  • If the user has only 2D elements in the model, the 2D Roadway Crossing panel will be displayed by default.
  • If the user has both 1D and 2D elements in the model, the 1D Roadway Crossing panel will be displayed by default.

The 1D Roadway Crossing panel allows the user to select the river, corresponding reach, and the roadway crossing river station from the River name, Reach name, and Roadway crossing river station dropdown combo boxes. Alternatively, the user can click the [Pick] button to select the roadway crossing river station from the Map View.

The 2D Roadway Crossing panel allows the user to select the 2D roadway crossing from the 2D roadway crossing ID dropdown combo box. Alternatively, the user can click the [Pick] button to select the 2D roadway crossing from the Map View.
2D Roadway Crossing tabbed panel

Extract Elevation Data

This section is used to define the elevation data source(s) to be used to extract the roadway geometry.
Extract Elevation Data section

The user can use the Primary and Secondary Elevation Data panels to define the primary and secondary (if available in the project) elevation data sources for extracting the roadway geometry. Different options are provided to specify additional elevation data information depending on the selected elevation data source type.

The following elevation data formats are supported:

  • CAD Drawing
  • Elevation Grid
  • GIS Contours
  • LandXML Data
  • Terrain Surface
  • TIN Surface

When a secondary elevation data source is available, the software will form a concave hull around the primary elevation data source to identify its bounds. For locations where elevation data from the primary data source is unavailable, the software will use the elevation data from the secondary data source.

Note that the user cannot utilize the same data source to define both the primary and secondary elevation data.

The user can click the [Swap Sources] button to swap the selected elevation source from primary elevation data to secondary elevation data and vice versa.

Extraction Specifications

This section is used to define the specifications for extracting the roadway geometry. The user can extract the high chord geometry of the roadway crossing and the internal bridge geometry. For 2D models, the user can also extract the elevation data from approach and exit cross sections.

The following panels are provided in this section:

High Chord Geometry

This panel is used to specify general parameters for extracting high chord roadway geometry. The extracted elevation at the roadway high chord vertices will get populated in the appropriate fields of the bridge and culvert data dialog boxes.
High Chord Geometry tabbed panel

By default, the options in this panel are disabled (i.e., grayed out). The user can select the Extract Elevation Data checkbox to enable the content of this panel. If this checkbox is left unchecked, the software will not extract high chord roadway geometry.

The following options are provided to extract elevation data:

  • Extract elevation data from roadway centerline
    On selecting this radio button option, the software will extract the elevation data using the roadway centerline.
  • Extract elevation data from roadway edges
    On selecting this radio button option, the software will extract the elevation data using roadway edges.

The following options are provided to assign elevations at roadway edges:

  • Assign elevations at upstream and downstream roadway edges
    On selecting this radio button option, the software will extract and assign elevations at both upstream and downstream roadway edges.
  • Assign elevations at upstream roadway edge only
    On selecting this radio button option, the software will extract and assign elevations only at the upstream roadway edge.
  • Assign elevations at downstream roadway edge only
    On selecting this radio button option, the software will extract and assign elevations only at the downstream roadway edge.

Internal Bridge Geometry

This panel is used to provide general specifications for extracting the bridge’s internal geometry. The extracted internal bridge geometry data will get populated in the appropriate fields of the bridge and culvert data dialog boxes.
Internal Bridge Geometry tabbed panel

By default, the options in this panel are disabled (i.e., grayed out). The user can select the Extract Elevation Data checkbox to enable the content of this panel. If this checkbox is left unchecked, the software will not extract the internal bridge geometry.

Note that the options provided to extract the elevation data in this panel are similar to that of the High Chord Geometry panel.

The following options are provided to assign geometry to internal cross sections:

  • Assign at upstream and downstream internal cross sections
    On selecting this radio button option, the software will extract and assign geometry for both upstream and downstream cross sections.
  • Assign at upstream internal cross section only
    On selecting this radio button option, the software will extract and assign geometry for only the upstream cross section.
  • Assign at downstream internal cross section only
    On selecting this radio button option, the software will extract and assign geometry for only the downstream cross section.

Other Data

This panel is enabled only for 2D roadway crossings. It allows the user to extract elevation data from approach and exit cross sections.
Other Data tabbed panel

The following parameters are provided in the panel:

  • Extract elevation data from 2D approach cross section
    Select this checkbox to extract elevation data from the approach cross section.
  • Extract elevation data from 2D exit cross section
    Select this checkbox to extract elevation data from the exit cross section.

When all the data has been defined, the user can click the [OK] button to extract and populate the roadway geometry data into the appropriate fields of bridge and culvert data dialog boxes.

About the Author Chris Maeder

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