> For the complete documentation index, see [llms.txt](https://docs-7.phoenixlidar.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs-7.phoenixlidar.com/lidarmill-desktop/workflow-kk/lidarsnap-v4/ground-control-with-lidarsnap.md).

# Ground Control with LiDARSnap

Ground control points (GCPs) can be used with LiDARSnap. Linear horizontal and/or vertical adjustments can be applied to point clouds using the [Apply Corrections](/lidarmill-desktop/workflow-kk/ground-control/adjusting-automatically-to-gcps-vertical-only.md) tool, however **LiDARSnap is able to apply a variable adjustment to control**, which may be required in some cases. 

If GCPs are present in a project, they will by default be enabled for use in LiDARSnap:

<figure><img src="/files/3K5Wc7X4r19bTbHeRVbL" alt=""><figcaption></figcaption></figure>

When performing trajectory optimization with GCPs enabled, LiDARSnap will consider the vertical position of **control points** when determining trajectory adjustments.&#x20;

{% hint style="info" %}
GCPs marked as **check points** are not used by LiDARSnap.
{% endhint %}