How to use GCPs for processing on PIX4Dcloud

Ground control points (GCPs) can be used for processing on PIX4Dcloud:

They need to be marked using PIX4Dmapper beforehand when processing on PIX4Dcloud.
They can be inserted and automatically detected on PIX4Dcloud Advanced using the AutoGCPs detection functionality.

This article focuses on how to use GCPs for processing on PIX4Dcloud without the flexibility of the AutoGCPs detection functionality that PIX4Dcloud Advanced offers. For more information about how to take advantage of this function: AutoGCPs detection functionality.

Access: To follow the workflow described in this article, both a PIX4Dmapper and a PIX4Dcloud license are needed.

Note: It is not required to process the project on PIX4Dmapper. Opening the project, adding and marking the GCPs is sufficient.

1. Open the project using PIX4Dmapper:

Create a new project from scratch but do not start processing. For more information: Step 2. Creating a Project.
Alternatively, download the project from PIX4cloud. For more information: How to download results from PIX4Dcloud.

2. On the menu bar, click Project > GCP / MTP Manager...
3. Select the GCP coordinate system.
4. Import the GCPs coordinates. For more information: How to import and mark ground control points (GCPs).
5. In the window GCP/MTP Manager, click Basic Editor...
6. In the section GCP/MTP Table, select the GCP to be marked.

7. In the section Images, sort the list:

By name: The images are sorted alphabetically.
By distance to GCP: Images closer to the GCP are listed first. This sorting can be used only if the images and GCPs are geolocated using a known coordinate system. This is the default sorting mode.
By distance to the marked image: When an image is selected and a GCP is marked on it, this option lists the images that are closer to the currently selected image. This sorting can be used only if the images are geolocated.

8. In the section Images, select the image on which the GCP should be marked. After the selection, the image is displayed in the Preview section.
9. Navigate in the image by:

Zoom in: Moving the mouse scroll wheel forwards.
Zoom out: Moving the mouse scroll wheel backwards.
Pan: Using the mouse left click.
Zoom in quickly on a specific point in the image: Point with the mouse the point and hit the Alt key. When the key is released, the view returns to the last zoom level.
Zoom out to preview the zero zoom level: Hit the Shift key. When the key is released, the view returns to the last zoom level.

10. Left-click on the image to mark the point. If needed, remove a mark by clicking .

11. In the Images section, select the next image on which the GCP should be marked.

Note: A GCP does not need to be marked on all images in which it appears. Ideally, mark a GCP on 3 to 8 images (minimum is 2).

12. Repeat steps 8 to 11 for the other GCPs.
13. Click OK.
14. On the menu bar, click Project > Save Project.
15. Ensure Step 1 is marked for processing. Mark Step 2 and 3 upon need.
16. Upload the project from PIX4Dmapper to PIX4Dcloud. For more information: How to upload project files from PIX4Dmapper to PIX4Dcloud.
17. After the project finishes processing successfully, the Geolocation details can be checked in the .PDF quality report that can be downloaded from the Files > Results section of the PIX4Dcloud project.