Hey TBC’ers! Happy holidays! Have you ever wanted to automatically extract solid single, solid double, and/or dashed lane lines with user-defined line styles and settings? For instance, you’ve scanned a road and you want to create linestrings and points from lane line markings extracted from a point cloud. In this week’s tip, the creation of a new linestring and points based on the extraction of a solid single lane line will be covered.
Follow the steps below to learn how to utilize the Extract Line Feature command to automatically detect and extract solid single lane lines.
- In the TBC ribbon, select Point Clouds > Deliverables > Extract Line Feature to display the Extract Line Feature command pane.
- In the Extraction type drop-down list, select Lane Line Markings.
Note: When Lane Line Markings is selected, the point cloud changes to Gray-Scale Intensity mode to better delineate the lane lines.
- Click the Line Settings drop-down group box to specify display properties for the linestring that will be created from the extracted lane line. (All Line Settings are optional.)
- Here, we will enter Solid Single in the Name field and select Cyan in the Color field.
- In the Lane line type drop-down list, verify Solid single is selected.
- In the Plan View, zoom in to clearly view your desired solid single lane line, as shown here.
- Click in the Line point field and then click on the solid lane line in the Plan View.
- When you click on the line, the following occur:
- The default intensity threshold is applied to the point cloud, causing the detectable lane lines in the point cloud to be highlighted in orange.
- A green cross displays where you clicked, indicating the starting point for the extraction.
- A white arrow displays indicating the direction of the extraction. The length of the arrow indicates the distance (as specified in Advanced Settings: Maximum interval) that will be searched along the line's path as the extraction is performed. If no applicable scan points are found within that distance, the extraction process stops. Linestring segment nodes are created intermittently along the line based on this distance as well.
- Optionally, click to expand the Advanced Settings drop-down group box. Experiment with the Intensity threshold slider to see the effects of the intensity threshold, as well as the Maximum interval field to specify the distance that will be searched along the line’s path as the extraction is performed. Here, we will not change these default settings.
- To specify that a new point be created at each linestring node, check the Create line node points check box in Advanced Settings and enter L1 in the Starting Point ID field.
- Click the Extract button. The extraction begins and continues until the end of the solid single lane line is reached, as represented by a purple line.
- To extract the single solid lane line in the opposite direction from your selected starting point, click the Switch Direction button.
- Click the Extract button to complete the lane line extraction to the other end.
- Click the Create Line and Points button. A new cyan linestring is created – each of its segment nodes includes a new point and point label.
- Click the Close button to close the Extract Line Feature command pane. In the TBC ribbon, select Point Clouds > Rendering > True Color.
- The point cloud is now displayed in True Color to get a better view
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