How to import and mark Ground Control Points (GCPs) in PIX4Dcatch

It is possible to capture and mark Ground Control Points (GCPs) in PIX4Dcatch projects. After the capture, select a Point Collection to start the process, allowing for PIX4Dcatch projects to achieve higher absolute accuracies that GCPs provide.

Obtain GCP Collection

GCPs are stored in a Point Collection with corresponding coordinates.

Important: Processing will use the Collection's coordinate system for the output coordinate system. Therefore the following has to be considered during GCP measurements:
  • Projected Coordinate Reference System is required.
  • Site Localization and Geographical Coordinate Systems are not allowed.

Measure GCPs in a project

PIX4Dcatch with the RTK rover can also be used to measure and collect GCPs

Tip: Add reference images of your GCPs and descriptions to help you, later on, to mark the GCP at the correct place.

Import GCPs to PIX4Dcatch

PIX4Dcatch is also capable of importing GCP coordinates into an existing Collection. If the desired Collection does not exist yet, please create it first. Then there is an option to Import Points. Please note that coordinates have to be in the same coordinates system as the Collection itself. For input format, please refer here: Tie points (GCPs, CPs) import format - PIX4Dmatic

Marking GCPs manually in a project

To use the GCPs in a PIX4Dcatch project, the Point Collection has to be assigned to a project; then the GCPs in the Point Collection have to be marked on the images. For more information, see: How to use automatic Tag Detection and manual GCP marking - PIX4Dcatch RTK

Processing a project with GCPs

For processing a project with marked GCPs, see: Processing projects - PIX4Dcatch