# Corrections

The Corrections window stores computed corrections, and enables users to apply rigid adjustments to the trajectory and pointcloud. The [Align to GCP](/spatialexplorer-8-and-9/user-interface/toolbars/workflow/ground-control.md) tool automatically creates vertical corrections in the Corrections window, however corrections can also be created manually from measurements:

## Creating Automated Vertical Corrections

Use the [Align to GCPs ](/spatialexplorer-8-and-9/user-interface/toolbars/workflow/ground-control.md)tool to create corrections from vertical residuals between GCPs and the pointcloud:

<figure><img src="/files/C6C1oszWWATCQEudnFd3" alt=""><figcaption></figcaption></figure>

## Creating Corrections Manually&#x20;

Corrections can also be created manually by selecting points or GCPs in the main view (creating measurements) and then using the **Import from Measurements tool.**

To create corrections manually, select a GCP and the corresponding point in the point cloud which should be co-located with the GCP:

<figure><img src="/files/dThXXWwBLE0z1Hhi2t6u" alt=""><figcaption></figcaption></figure>

You should then have two entries in the measurement window, one with source (SRC) PointCloud, and one with source GroundControl:

<figure><img src="/files/5LyHV9nNNy4CsAO85rMh" alt=""><figcaption></figcaption></figure>

{% hint style="warning" %}
Keep the Measurements window clean! A correction must be between two points, either one GCP and one pointcloud point, or two points in the pointcloud. If your measurements window has more than two entries, a correction cannot be created.
{% endhint %}

Use the **Import from Measurements** button to import the measurements as either a Vertical, Horizontal, or Full correction:

<figure><img src="/files/AAiYmAIGRMn8zrRkLT32" alt=""><figcaption></figcaption></figure>

{% hint style="info" %}
If you intend to run LiDARSnap with manual corrections enabled, the correction must be a Full (i.e. horizontal and vertical) correction.&#x20;
{% endhint %}

After creating the correction, you should see it as an entry in the **Corrections** window, as well as visualized in the main view:

<figure><img src="/files/cwLmkMZJUX8IWwRJEcmP" alt=""><figcaption></figcaption></figure>

A correction can also be created from two points in the pointcloud, or between two points in two different pointclouds. To create a correction from two pointcloud points, disable the **GCP-point corrections** option:

<figure><img src="/files/tXzVBVkH2JvTixJFSh1c" alt=""><figcaption></figcaption></figure>

## Applying Corrections

{% hint style="warning" %}
If you are creating corrections to be used with LiDARSnap, do not attempt to apply corrections, as discussed below. For LiDARSnap, Full corrections should be present in the corrections window.&#x20;
{% endhint %}

Corrections can be applied to the active trajectory. This is useful when a single, global shift of the data set is required. Corrections are averaged amongst type, meaning that all vertical corrections are averaged to determine a single vertical adjustment, and all horizontal corrections are averaged to obtain a single horizontal shift:

<figure><img src="/files/F4PUbuHI3pbfLuVcxM21" alt=""><figcaption></figcaption></figure>

Applying a correction to the active trajectory will create a new trajectory with the applied shift.&#x20;


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