Georeferencing Roadway Segments

The process of georeferencing a roadway segment to the Map View can be a trial-and-error process—especially when the exact location of the original roadway segment is not known. In this scenario, the Georeference Roadway Segments command allows the user to manually georeference each of the roadway segments to the background base map displayed in the Map View.

Note that a CRS should be assigned before running this command. Otherwise, the software will display the informational dialog box that appears below.

Refer to this article in our knowledge base to learn how to assign a coordinate reference system to a project.

Follow the steps below to use the Georeference Roadway Segments command:

1. From the Input ribbon menu, click the Roadway Gutter/Ditch/Inlets dropdown menu and select the Georeference Roadway Segments command.
   
2. The Georeference Roadway Segments dialog box will be displayed.
   

The following sections describe how to georeference an existing roadway segment and interact with the above dialog box.

Selecting Roadway Segment to Georeference

The Select Roadway Segment to Georeference section allows the user to select the roadway segment that is to be georeferenced.

Follow the steps below to select the roadway segment to be georeferenced:

1. Select the roadway segment from the Roadway segment ID dropdown combo box that lists all the roadway segments contained within the project.
   
2. Alternatively, the user can click the [Pick] button to select the roadway segment from the Map View. After clicking the [Pick] button, the Georeference Roadway Segments dialog box will temporarily disappear, and a prompt will be displayed on the status bar instructing the user to select the roadway segment from the Map View.
   
   
3. Upon selecting the roadway segment, the dialog box will be redisplayed, and the selected roadway segment will be highlighted on the Map View. The user can click the [Clear] button to cancel all the previous selections and redo the entire process.Note: If the model contains a single roadway segment, then it will be selected automatically in the Roadway segment ID dropdown combo box.

After selecting a roadway segment, the user can select one of the following options to georeference roadway segments:

• Snap to Alignment Polyline
• Slide Along Alignment Polyline
• Draw on Map View

Snapping Roadway Segment to an Alignment Polyline

If an existing alignment polyline for the roadway segment exists on the Map View, the Snap to Alignment Polyline georeferencing option can be used to snap the selected roadway segment to the alignment polyline.

Follow the steps below to use the Snap to Alignment Polyline georeferencing option:

1. Select the Snap to Alignment Polyline radio button option to enable this section.
   
2. Click the [Pick] button next to Select alignment polyline read-only field.
   
3. The Georeference Roadway Segments dialog box will temporarily disappear, and a prompt will be displayed on the status bar instructing the user to select the alignment polyline from the Map View.
   
   
4. Upon selecting the alignment polyline, the Georeference Roadway Segments dialog box will be redisplayed and the status of the Select alignment polyline read-only field will change from Not Selected to Selected. The user can click the [Clear] button to cancel all the previous selections and redo the entire process.
   
   
5. Click the [Snap] button to snap the selected roadway segment to the alignment polyline.
   

Sliding Roadway Segment Along Alignment Polyline

If a roadway segment has been snapped to an alignment polyline but is not precisely located where it should be, the Slide Along Alignment Polyline georeferencing option can be used to slide the roadway segment along the alignment polyline.

Follow the steps below to use the Slide Along Alignment Polyline georeferencing option:

1. Select the Slide Along Alignment Polyline radio button option to enable this section.
   
   
2. Click the [Pick] button next to the Select alignment polyline element read-only field.
   
3. The Georeference Roadway Segments dialog box will temporarily disappear, and a prompt will be displayed on the status bar instructing the user to select an alignment polyline from the Map View.
   
   
4. After selecting the alignment polyline, the following Snap Entity dialog box will be displayed. Click the [Yes] button to select the polyline or click the [No] button to abort the selection and redo the entire process.
   
5. Once the alignment polyline is selected, click the [Slide] button from the redisplayed Georeference Roadway Segments dialog box.
   
6. The Georeference Roadway Segments dialog box temporarily disappears, and a prompt will be displayed on the status bar instructing the user to select the roadway segment and drag it along the underlying alignment polyline.
   
   
7. Click and drag the roadway segment on the Map View to revise its alignment.
   
   
8. When finished, the user can press the [Enter] key or right-click and select Done from the displayed context menu. The Georeference Roadway Segments dialog box will be redisplayed, and the roadway segment will be georeferenced at the new location.
   
   
9. The user can also check the Recompute adjacent node element elevations checkbox option to recompute the elevation of the adjacent node type elements while georeferencing the roadway segment. By default, this checkbox is checked.Note that if the end points of the roadway segment do not overlay the same continuous alignment polyline, then the following informational dialog box will be displayed.
   

Drawing Roadway Segment on Map View

The Draw on Map View georeferencing option allows the user to draw an alignment polyline on the Map View and automatically snap the selected roadway segment to the drawn polyline.

Follow the steps below to use the Draw on Map View georeferencing option:

1. Select the Draw on Map View radio button option and click the [Draw] button.
   
2. The Georeference Roadway Segments dialog box will temporarily disappear, and a prompt will be displayed on the status bar instructing the user to draw an alignment polyline on the Map View.
   
   
3. Draw the alignment polyline on the Map View. When finished, press the [Enter] key or right-click and select Done from the displayed context menu.
   
   
4. The Georeference Roadway Segments dialog box will be redisplayed, and the selected roadway segment will then automatically snap to the drawn alignment polyline.
   
   Notes:
   • The user can check the Create curvilinear polyline checkbox option to draw the polyline using a curvilinear segment. Refer to this article in our knowledge base to learn more about element digitizing on the Map View.
   • The user can check the Scale to fit checkbox option to scale the roadway segment to fit within the alignment polyline.

Assigning Roadway Segment Invert Elevation

The user can check the Assign Roadway Segment Invert Elevation checkbox option to assign an invert elevation to the roadway segment using a terrain model. The user should define the data for this section before georeferencing the roadway segment so that the invert elevation can be assigned.

To assign an invert elevation, the Terrain elevation source dropdown combo box supports the following surface types:

• CAD drawing
• Elevation grids
• GIS contours
• LandXML data
• Terrain surfaces
• TIN surfaces

Depending upon the elevation data source type selected, different options are provided to specify additional elevation data information. The user can define an invert depth using the Roadway Segment invert depth entry field to raise or lower the invert of the roadway segment by the specified amount. A negative invert depth value lowers the roadway segment by the specified amount.