Linear Facility Extraction
- Function Description: Based on established templates, linear facility extraction can be performed. There are four modes: By Direction, By Path, Draw Path, and At X-Section to meet different usage scenarios.
Parameters
Template: The template used for the current extraction. Clicking Flip will mirror the template and use the mirrored template for extraction.
Mode: Extraction mode for different usage scenarios, meeting different scenario requirements through different interaction logic.
Layer: Location where extraction results are saved.
Step: Frame interval during the extraction process. It is recommended to increase the step size in straight sections and decrease it in curved sections.
Manual Adjustment: When checked, the extraction will pause after each frame extraction, waiting for the user to manually correct the key point matching position until the user provides confirmation before proceeding to the next frame extraction. When the extraction success rate is very low, you can check this option to manually optimize the extraction results.
Range: Defines the data range on the cross-section centered on the point drawn by the mouse, removing outliers outside the range. For objects that are too large or too small, targeted adjustments are needed. In the 3D view, the profile range is displayed as a green box, which can intuitively discover whether the range setting is appropriate.
Class: Point class participating in extraction.
Thickness: Profile thickness during extraction.
Max Error: For a single frame, if the matching error of the current frame is greater than the maximum error, the extraction result of that frame will be discarded.
Curve Smoothing: When checked, the vector line will be geometrically smoothed after extraction, which can improve the unevenness of the vector line.
By Direction
This mode is suitable for highway guardrail scenarios, which have the characteristics of clear geometric features and few debris.
Draw an initial forward direction at the starting position of the guardrail (preferably in a straight section) (the program will perform automatic extraction along this direction. During the extraction process, the forward direction is automatically corrected based on the extraction results until extraction fails);
Wait for the automatic extraction to complete.
By Path
This mode is suitable for road edge and urban guardrail scenarios. These scenarios have weak geometric features and are easily mixed with low vegetation, which tends to deviate from the correct direction in the By Direction extraction mode.
First use the Vector Editor or Map Element tool to draw the approximate path position of the road edge;
Switch to the By Path mode in Linear Facility Extraction;
Click to select the drawn path line in the 3D view;
Wait for extraction to complete.
Draw Path
Similar to the By Path mode, this mode is also suitable for road edge and urban guardrail scenarios. However, Draw Path is more flexible, supports modifying path positions midway, and allows rollback.
Switch to the Draw Path mode in Linear Facility Extraction;
Draw a path along the road edge. Each time a new path point is added, the program will extract from the previous endpoint to the new path point according to the set step size;
If there is an error in the extraction result, you can right-click to rollback frame by frame, then adjust the view and redraw the path;
Press Enter to end extraction.
At X-Section
This mode is suitable for scenarios where there is no suitable viewing angle in the 3D view, the surrounding environment is cluttered, making it impossible to accurately capture the object position, but interaction is easy in the profile view, such as urban pipelines.
Switch to the At X-Section mode in Linear Facility Extraction;
Draw a profile in the 3D view to determine the initial extraction position;
Adjust the Range parameter according to the green box displayed in the profile view, making the green box fit the target area as closely as possible to avoid matching failure;
- Move the mouse position so that the green box fits the target area as closely as possible, then click to complete the current frame extraction;
Note: In a cluttered pipeline environment, it is very necessary to make the green box fit the target area as closely as possible.
Observe whether the extraction result is accurate. If accurate, click Accept to proceed to the next frame extraction. If not accurate, drag the key points to the correct position, then click Accept. If the point cloud of the current frame is particularly cluttered and it is impossible to determine the accurate key point position, click Skip.
Repeat steps 4 and 5 until the extraction of the entire pipeline is completed, then click Finish to end extraction.
