You can make the following changes to the processed data:

Item Correction

To correct an item:

  1. Double-click where you want the change to take effect, then select New Correction. The Correction Item dialog appears and an inverted triangle marks where you clicked. The Item picked displays at the top of the Correction Item dialog.
  2. In the Correction Item dialog, select the desired option. The following sections describe the options.

DEM Changes

DEM is computed by a combination of "crawling algorithms" and "sensitivity algorithms." The sensitivity algorithms are used in rough terrain or where the crawling algorithms cannot bridge a gap.

To implement manual DEM changes, perform a full reprocess.

  • DEM - Add To Terrain: Use when the ground failed to reach a terrain area. Increase the Radius to cover the path that enables the crawling algorithms to get to the area.
  • DEM - Remove From Terrain: Blocks the crawling algorithms from reaching building roofs or roofs of building parking lots. A blocked roof is reclassified as a building.
  • DEM - Filter Points in Radius: Marks groups of points to ignore in DEM calculation. Such points may be caused by the LiDAR beam hitting a laser delaying material (points under the ground), or "birds" (points above the area and features). Enter the Radius that the change will effect; the radius to be effected displays on the DEM surface as you change the setting.
  • DEM - Level Area: Flattens the DEM in the set radius at the elevation of the selected point. This is usually used to filter vegetation or water wave noises.

Building Changes

To implement manual building changes, you can re-export (exit QA Mode, then select File > Export > Buildings), or perform a full reprocess.

  • Building - Set: The selected points become a starting point for planes searching by ENVI LiDAR. This reduces limitations set on noise in the automatic process, thereby increasing the ability of ENVI LiDAR to set a plane at the designated point.
  • Building - Set as Boxed: Calculates the perimeter of the building and sets the roof to be flat. Use this option when there are holes in the data, or when there is a local reduction in laser point density.

To add or edit buildings, see Edit or Add Building Vectors.

Tree Changes

To implement manual tree changes, you can re-export (exit QA Mode, then select File > Export > Trees), or perform a full reprocess.

  • Tree - Set: Add a tree at the designated location. Specify the Radius and Height in the fields provided.
  • Tree - Edit: Edit the dimensions of the selected tree. When you click on the tree, the current dimensions appear at the upper part of the Correction Item dialog. Specify the Radius and Height in the fields provided. The tree symbol on the screen changes according to the numbers entered, enabling you to adapt the tree dimensions to the points.
  • Tree - Remove: Delete the selected tree.

Power Pole and Power Line Changes

To implement manual power line changes, you can re-export (exit QA Mode, then select File > Export > Power Lines), or perform a full reprocess. Performing a full reprocess also updates the power poles shapefiles.

  • Power Pole - Set: Add a power pole at the designated point. Radius and Height are calculated by ENVI LiDAR.
  • Power Pole - Remove: Delete the selected power pole. Use when there are parallel lines and ENVI LiDAR sets one pole in the middle of two lines. You must set the two poles manually. Another method to remove a pole is to delete the correction mark that marks each power pole.
  • Power Line Attachment - Set: Add a power line attachment point at the designated point. Several attachment points in the same location will automatically define a power pole.
  • Power Line Attachment - Remove: Deletes the selected power line attachment point.

Changes are marked with an inverted triangle. When the cursor is placed on a change triangle, the coordinates and the change details display in the status bar of the Main window. Right-click the triangle and select Edit to edit settings and highlight the change and the effect radius.

To add or edit power line vectors, see Edit or Add Power Line Vectors.

Change Point Classifications

You can manually classify points by selecting a contour in the Cross Section window and assigning a classification to the points bounded in this volume.

To implement manual point classification changes, you can re-export (exit QA Mode, then select File > Export > Point Cloud), or perform a full reprocess.

To change a classification:

  1. Create a cross section where you want to change the classification.
  2. Increase/decrease the cross section Thickness and zoom/pan the Cross Section window so that it includes the points that need classification.
  3. In the Cross Section window, double-click where you want to make a change and select New Correction with Contour.
  4. Click on the cross section display to generate a contour line. Close the contour line by right-click. The Correction Item dialog appears.
  5. Enable the Change Classification Code radio button.
  6. Choose what class to reassign the selected points to from the Classification drop-down list. The options are:
    • Unclassified: Classify points that do not belong to a needed layer.
    • Terrain: Classify points as terrain points.
    • Near Terrain: Classify points that belong to low vegetation, fences, and other low objects.
    • Under Terrain Noise: Classify under terrain points (usually caused by reflections from glass objects). May be used to eliminate noise above terrain as well.
    • Buildings: Classify points as building points.
    • Trees: Classify points as trees points.
    • Power Lines: Classify points as power line points
    • Power Pole: Classify points as power pole points.
  7. Click OK. A triangular marker appears where the change occurred. The color of the points change to the color of the selected class to indicate that the change took effect.
  8. To edit or change a contour, right-click on the change marker, then select Edit, Edit Contour, or Delete.
  9. Selecting Edit Contour highlights the contour and its intersection points. Right-clicking the contour line opens a context menu that allows you to Add Point, Save Correction, or Delete Correction. Right-clicking on a point allows you to delete the point. Clicking on a point and dragging it moves the point to a new location. You must Save Correction or Delete Correction to exit the Edit Contour mode.
  10. You can view all the contour classification changes on the screen in QA Mode by enabling the Correction Contours option in the Layer Manager. The contours are colored according to the classification selection.

Edit or Add Building Vectors

You can manually edit existing building vectors and you can manually add new building vectors where ENVI LiDAR did not create them automatically. ENVI LiDAR positions an initial plane in the designated place. This initial plane is oriented automatically by ENVI LiDAR to match the points within a meter around the designated place.

To implement building vector changes, you can re-export (exit QA Mode, then select File > Export > Buildings), or perform a full reprocess.

To edit an existing building vector:

  1. Select the building vector by double-clicking on the plane surrounded by the vector line. The selected vector is highlighted and a context menu appears.
  2. Select Edit Building Contour from the context menu. The Main window shows the selected contour, the points within the Thickness distance from the plane, the intersection lines of the selected plane with the adjacent planes, and the corners of the adjacent planes. This helps you to edit the vectors and easily place them at the correct orientation with respect to the points, and with respect to the other planes.
  3. In the Cross Section window, right-click on a vector point or line and select a menu option to edit the selected building contour.

  4. Save or delete corrections by using the right-click menu.

    The following keyboard shortcuts are available when you left-click on a vector:

    • Press a to add a point. Drag the point to the desired position, then click to set it.
    • Press r to remove a point. To remove multiple points, press and hold R and move the cursor over the points to remove.
    • Press m to remove multiple points, then click and drag the cursor to select the points to remove.
    • Press s to save the change.

    • Press d to delete the correction.

Note: During editing, the vector may cross itself, which generates an error message. You need to remove additional points or add points to resolve the error.

To add vectors:

  1. Double-click on the points that create the plane. The Correction Item dialog appears.
  2. Click New Building.
  3. A small rectangle is created, ready for you to edit. ENVI LiDAR orients the plane according to the points around the designated place. Before editing the plane, verify this orientation by looking at a profile view of the plane in the Main window.
  4. Move the rectangle points and add or remove points to match the required plane.
  5. Once the vector fits the required plane, right-click on its line, and select Save Correction.

Note: ENVI LiDAR might not be able to detect the initial plane angle due to noise in the designated area, which generates an error message. Choose another place and try again. You might also need to adjust the Plane Surface Tolerance setting for buildings in the Production Parameters tab.

Edit or Add Power Line Vectors

You can manually delete or edit existing power line vectors and you can add new power line vectors where ENVI LiDAR did not create them automatically.

To implement power line vector changes, you can re-export (exit QA Mode, then select File > Export > Power Lines), or perform a full reprocess.

To delete or edit an existing power line vector:

  1. Select the power line vector by double-clicking on its vector. The selected vector is highlighted and a context menu appears.

  2. Select Delete Power Line, or select Edit Power Line to make changes to the power line vector.

    Selecting Edit Power Line opens a cross section at the power line plane. All vectors and points bounded by the cross section volume are included. The selected power line, as well as the start point, end point and middle point are highlighted.

  3. You can move each of the selection points of the vector in order to match the vector to the points or attachment points. ENVI LiDAR automatically snaps the end points to the end points of adjacent vectors.

  4. Save or delete corrections by using the right-click menu.

    The following keyboard shortcuts are available when you left-click on a vector:

    • Press s to save the change.
    • Press d to delete the correction.

To add a new power line:

  1. Create a cross section in the plane of the power line by using another power line vector as a reference, or by using the power line points as a reference.
  2. Double-click in the Cross Section window where you want to generate the power line.
  3. Select New Power Line.
  4. A power line with three movable boxes appears. Move the boxes to the correct location to match the points.
  5. Hold the cursor over the new power line and press S to save it.