Control Points Report Dialog

Requires an LP360 Drone, Land Standard or Geospatial Basic or higher license.

Before working with the Accuracy Estimation dialog, ensure the Type column of your Control Points is correctly imported.

The Control Points Report dialog is opened by pressing the Accuracy Estimation on the Control Points Tab of the ribbon.

The Control Points Report Dialog is a dynamic control that can be opened alongside the map and used to compare a set of control points or check points with a point cloud surface. The comparisons or errors are displayed in the table and then reported as RMSE_z and Accuracy_z statistics for determining if the surface meets a given level of mapping standards. The Accuracy_z report can then be exported to a text file.

You can also perform X, Y, planimetric, and vertical measurements and see the results reflected in the points summary table. When you select a point in the table, you can click the measure tool to re-measure that point in the map, if necessary. Double-clicking on the point in the table takes you to that point in the map.

Statistics Summary and ASPRS

The statistics and the ASPRS will show the values necessary to determine the accuracy of the LIDAR surface used in the report. The values in the "Error" column and the accuracy XYZ columns of the Control Point List are used to produce the statistics, and points that are unchecked in the list are excluded from the statistics.

Learn more about the Statistical Summary Values
Learn how to Set Survey Control Error

How to exclude a Control Point from the report

A control point or check point may be excluded from the report if you find the control point to be an outlier or if you simply do not want to use the point in the overall report. After exclusion, you may at any time include the point back into the report. The statistical summary values are updated each time a point is included or excluded from the list.

Every point that is unselected will be excluded from the report. In the example the points PT1 and PT2 are excluded from the report.

Delta Z Only

This tool will force the Control Points only to measure automatically the Z axis. Even if the point can be automatically measured in X and Y.

Auto Find

Control Points will try to auto find all the Control Points added. Depending on the type, it will be measured in Z only or in X, Y and Z.
Note: for the control points to be able to Auto Find points in the 3 Axis, it is required 3D Accuracy and the user of one of the following point types (AS, SN, ST, CB, CV or CO).

Solve

Solve is a task to be performed after measuring (Auto Find) the Control Points. This task is used to debias the point cloud by suggesting to the user the measured bias values. These values can be extracted from the "Mean Error" statistics of the Control Report.
The correction is performed via an Affine Transform, LAS Point Cloud Task.

The debias task can be performed in translation (Tx, Ty and Tz), and optionally rotation (Rx, Ry, Rz), where a non-zero origin (Ox, Oy and Oz) may be specified.

Auto Solve

Enabling this option will automatically compute the debias values without the need to press the "Solve..." button.

Apply Correction

Opens the LP360 Control Points Report Apply Correction dialog showing the computed correction values, and allowing the user to modify before applying to the Active LAS Layer. 

Output Layer Name: Introduced in 2025.2, the user may specify the name for the corrected LAS Layer, for example, "Debiased LAS", in place of the default name, "<Default>", where the legacy auto-naming convention is used, "LAS_Layer#".

Settings

There are multiple settings that can be selected to measure control points.

Z Probe Location

The Z Probe Location determines where the elevation of the surface model is computed. This setting works in conjunction with the Calculate DZ command. The Z Probe Location determines which set of X,Y coordinates to use to calculate dZ for the control point.

• Control X,Y:  Selecting Control X,Y uses the control point to probe and obtain the Z value.
• Measured X,Y: Selecting Measured X,Y uses the X,Y coordinates that you have measured for the control point to probe and obtain the Z value.

Input Points Filter

The Source Points filter defines which points are used to define the surface. Typically, only the bare earth points are used when producing a control point report. The Input Points Filter is used to modify the filter.

Input Points Filter: This option allows the user to filter the desired points to be considered as input. By default, all points are selected.

Method

Learn more about the different surface methods.

TIN: Recommended for Geospatial datasets. Not recommended for Drone or Land users.
Creates a mesh of non-overlapping triangles using the nearest surrounding points from the point cloud.

Inverse Distance Weighting (IDW): Recommended for Drone and Land users.
Estimates the value at the check point based on a set of nearby points, weighting each point’s value inversely to its distance from the check point. Closer points have more influence on the result.

• Power: Input a power greater than 1. The power shifts focus of the interpolation from local to global. A large power results in less influence from surrounding points (nearby data has more influence) resulting in more detail (less smooth). Small power values will result in a smoother surface and give points further away more influence in the interpolation.
• Fixed radius: Input a radius greater than zero. The radius influences the characteristics of the surface by limiting points around a point being interpolated. Larger radius will use more points in the surface calculation than would a smaller radius.
• Minimum neighbors: minimum number of points or neighbors to define the radius used in the interpolation. Using a minimum number of points increases the radius until the number of points criteria is achieved, thus eliminating the effect of the gaps in the data.

Accuracy Star

Intensity Coefficient: The proportion of the points that will be used based on intensity.

Tripod Height: The approximate measurement from the ground to the base of the tripod where it is installed on the Accuracy Star. It is recommended to use a value lower than the height of the accuracy star relative to the ground.

Checkerboard/Concentric

Target Size: Average dimension of one side of the checkerboard or diameter of the concentric target.

Export Report

The contents of the Control Point Report dialog can be written to a text file for future use. All aspects of the dialog are written to the report including, the surface method and the source points filter used for the surface.

Quick Set

The Quick Set control on the Control Points Report dialog box lets you select points in the table based on type. It is simply a quick way to select All points, if they are not already selected; Control to select all control points only; or Check to select all check points only. You will see the points checked in the very left column of the table based on your selection.

Unique Name Field

The Name Field on the Control Points Report dialog allows you to select an attribute to use to identify the points in the list, as they are listed in the Name column. These attributes come from the points' ASCII file. 

Measure Mode

The measure mode allows the user to manually measure the horizontal position of a control point in the point cloud.

1. Enable "Measure Mode".
2. Select a Control Point in the Control Points Report dialog.
3. In the map view, zoom/pan to the Control Point to be able to comfortably measure its location.
4. Measure the point by clicking the location of the control point in the point cloud. The location will be recorded in Measured X, Y and Z columns for that Control Point in the Control Points Report dialog.
5. To measure another Control Point, select the next Control Point in the Control Points Report dialog and the map window will automatically zoom the point.

Precision

The precision, or number of decimal places for the values used in the report, are determined by the value you enter in the Precision field. The precision is used only for presentation of values in a hard copy report or on the dialog. The calculations used to produce the output summary values use unrounded values to the limits of the operating system.

Image Explorer

Synchronizes the Image Explorer with the Control Points Report dialog to automatically load the closest georeferenced photo(s) from a photo layer to see the selected Control Point. This is useful for TrueView 3DIS payloads with both lidar and photo.

How to use the Control Points tools

See the LP360 Short Tutorial - Control Report for a video tutorial with the Control Points Report dialog.
Learn how to use the Control Points tools for Drone and Land project with this article.