Extract Point Features from a Point Cloud

Use the Extract Point Feature command to select a feature object in a point cloud (for example, a tree, pole, sign, or closed manhole) and automatically create a new point at the base/center of the feature with an assigned feature code and feature attributes. To assist in populating attribute values for the feature from extracted scan data, you can map the feature code's attributes, which are defined in an imported Feature Definition (.fxl) file, to attributes extracted by the command. For any feature attribute that cannot be mapped to an extraction attribute, you can enter the attribute value manually. This provides a quick, flexible, and efficient means of extracting features and attributes in scanned areas.

The attribute mapping you perform can be saved as a map in a Feature Extraction Attribute (.exl) file and shared with other users who can import it into their project and be assured their mapping matches yours, without the need to manually repeat the map creation process. For additional information, see Export Feature Extraction Attribute Map Files (.exl) and Import Feature Extraction Attribute Map Files (.exl).

Note: As an alternative to exporting and importing Feature Extraction Attribute Map files, you can perform attribute mapping in your project and then save the project as a VCT project template that can be used for other projects and by other users.

Prerequisites:

See the Subscription Plans page. For a license matrix by command, see the License page in the TBC Community. Also see View and manage licensed features.

To extract point features from a point cloud:

If you have not already done so, import the appropriate Feature Definition (.fxl) file into your project as described in Import Feature Definition.
This will enable you to map feature code attributes defined in the Feature Definition Library to attributes defined for the extraction type you select to use to create point features.
Note: If you do not import a Feature Definition Library (.fxl) file into your project, you can still extract points with assigned feature codes, but you cannot map or manually enter attributes for the features as described below.
Optionally, import a Feature Extraction Attribute Map (.exl) file into your project that defines a feature attribute/extraction attribute map to use in the point feature extraction process as necessary.
See Import Feature Extraction Attribute Map Files (.exl) and Export Feature Extraction Attribute Map Files (.exl).
In the 3D View or Plan View, display the scan points from which you want to extract point features.
You can select to not filter the graphic view at all if you expect to extract features from all of the scan points in the project. Or, you can select to filter the graphic view using the View Filter Manager to display only the point cloud regions from which you want to extract features. In addition, you can use the point cloud Keep Out and Keep In commands to further filter the view. This can be very useful when using the automatic extraction method (see below) if, for example, you are importing multiple point cloud regions into your project over multiple days of scanning. You can select to apply the automatic extraction command to just the newest imported point cloud region without re-extracting features that were previously extracted, resulting in duplicate point features.
Notes:
- To ensure the fastest performance, avoid making changes to view filtering (for example, using the View Filter Manager) while the Extract Point Feature command is running. Zooming in or out and panning do not affect performance.
- To help ensure successful point feature extraction, try to use adequately dense point clouds.
Select Extract Point Feature in Point Clouds > Extraction.
If a message displays recommending that you classify point cloud regions (classification has not yet been performed in the project) prior to performing point feature extraction, do either of the following:
- Click Yes to display the Extract Classified Point Cloud Regions command. Then, classify the regions mentioned in the message or, optionally, classify all of the regions. See Extract Classified Point Cloud Regions for instructions.
  This step is optional, but highly recommended. It helps ensure faster processing times and higher accuracy when performing point feature extraction. And, the classified regions are saved in the project so the classification process needs to be performed only once, regardless of how many times you run the Extract Point Feature command.
- Click No to close the message without classifying the regions. This will typically result in longer extraction times and lower accuracy.
In the Extraction type drop-down list, select the type of feature for which you want to extract a feature point.
Your selection determines the extraction attributes, which are displayed in the right column of the Mapped section in Attribute group, to which feature code attributes can be mapped.
Note that two options are available for extracting manholes. Select Manhole - Photogrammetry when the point cloud was created from aerial photogrammetry. Select Manhole - Laser Scanner when the point cloud was created from a terrestrial laser scanner.
Note: If you select the Manhole - Photogrammetry Extraction type when working with aerial photogrammetric point clouds, ensure an adequate flying height was used so that the features are distinguishable and visible. The quality of the point cloud plays a big role as well. When generating a point cloud from aerial photogrammetry data in TBC, in the Elevation type drop-down list be sure to select the Digital Surface Model (Highest Quality) option with the Point Cloud density set to Medium or High. DSM (Highest Quality) uses Semi Global Matching (SGM) to obtain higher quality deliverables than those provided using the other DSM option.
If the extraction type includes an attribute for the diameter of the selected feature, click the Settings link located above the Extraction type drop-down list and select how the diameter of the selected feature object is to be measured.
Select the appropriate extraction method option:
- Manual - This method allows you to pick features for extraction individually, one at a time. Depending on your point cloud and the precision with which selections must be made, or the number of features you expect to extract, this may be your best option. Instructions...
- Automatic - This method enables the software to automatically extract at the same time all of the features of the selected extraction type included in a filtered or unfiltered view. No manual selection is required. This method is less accurate than the Manual method, but it can greatly speed up the extraction process, and it allows for corrections. Instructions...