Categorising Points

When you wish to select a small portion of points, you can select points in the scene and assign them to categories. This adds a new column to the points object, preserving the original data.

The rest of this topic describes how to categorise points in the scene. It is divided into:

Creating a Category Selection

To start categorising points, right-click on the points object in the project tree and select New Category Selection.

The New Category Selection window will appear:

If you select an existing column as the Source Column, you can assign selected points to the existing categories or create new categories. If you select <None> for the Source Column, you will have to define each category manually.

When you click OK, the points object will be added to the scene, along with a set of tools for selecting points:

The Category Selection Toolbar

The first four tools in the category selection toolbar are the primary tools for selecting points in the scene:

The Select Points tool () is for drawing across points in the scene. This tool adds points to or removes them from the current selection, depending on which of the Add Points() or Remove Points() tools is also enabled:

  • If Add Points() is enabled, drawing across points adds them to the current selection.
  • If Remove Points() is enabled, drawing across points removes them from the current selection. Drawing across unselected points will have no effect.

Selected points are highlighted in the scene.

You can change the width of the line used by the Select Points tool by clicking on the second button in the toolbar:

The number shown as part of the Change line width button is the currently set line width.

You can keep this window open while selecting points so you can increase the line width to choose more points or reduce the line width to select fewer points.

You can also:

  • Select all visible points by clicking on the Select all button () or by pressing Ctrl+A.
  • Clear all selected points by clicking on the Clear selection button () or by pressing Ctrl+Shift+A.
  • Swap the selected points for the unselected points by clicking on the Invert selection button () or by pressing Ctrl+I.

Selecting Points and Creating Categories

To start selecting points, click on the Select Points button () and click the Add Points button (). In the scene, draw across each point you wish to select:

Selected points are highlighted in the scene. If you accidentally select the wrong point, either:

  • Click the Remove points tool () and draw across the point once again.
  • Hold the Ctrl key while drawing across the point.

When you have selected at least one point, click on the Assign to button, then select Create New Category:

Enter a Name for the new category, then click OK.

The new category will be created and the scene updated to reflect the changes:

Once you have created a new category, you can:

  • Assign more points to the category. Select points in the scene, then select the category from the Assign to list.
  • Rename the category. Click on the category in the list, then click the Rename button.
  • Delete the category. Click on the category in the list, then click the delete button (). When you delete a category from the list, all points that have been assigned to that category will revert to having no category assigned to them.

When you are finished, click the Save button ().

The new category column will appear in the project tree as an additional category column in the points table. Select the new column from the shape list to display it.

When you have finished selecting points and adding them to categories, close the Category Selection window to close the editor.

Editing a Category Selection Column

If you wish to make further changes to a category selection column, either:

  • Double-click on the column in the project tree.
  • If the column is displayed in the scene, click on the Edit button () in the shape list.