# Control Point Clouds Similar to using ground control with LiDARSnap, a control point cloud can be used as input for LiDARSnap. Below illustrates an example of resolving vertical offsets using a control point cloud:

Before Optimization - Red = Calibrated aerial dataset (Control cloud), Grey = Mobile point cloud from tightly coupled trajectory

After Optimization - Red = Calibrated aerial dataset (Control cloud), Grey = Mobile point cloud from LS4 optimized trajectory

Control point clouds can be used in two different ways: ### Calibrating one dataset to another Control point clouds can be particularly useful when one cloud is of a much higher accuracy and reliability than another cloud (e.g. using an aerial cloud as control when adjusting a mobile or SLAM cloud). This process uses the **Calibrate Dataset to Another Dataset** mode. ### Calibrating sensor to sensor within the same dataset This mode is used for calibrating an auxiliary sensor, such as with multi-sensor mobile systems or systems that use a secondary sensor for SLAM navigation. *Within the same dataset* refers to the sensors' data both referencing the same trajectory. --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://docs.phoenixlidar.com/spatialexplorer-8-and-9/user-interface/toolbars/workflow/lidarsnap-v4/control-point-clouds.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.