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AutoGCPs detection functionality - PIX4Dcloud Advanced

The AutoGCPs detection functionality in PIX4Dcloud Pro allows automatic detection of Ground Control Points (GCPs) and Check Points (CPs) within a dataset. This feature simplifies georeferencing and improves project accuracy by analyzing GCPs/CPs directly during processing.

IN THIS ARTICLE

Image and GCPs/CPs requirements
Upload the GCPs/CPs file
Defining the GCPs/CPs coordinate system
Viewing and editing the defined control points
Start processing

Licenses: This article is only valid for PIX4Dcloud Pro licenses (formerly PIX4Dcloud Advanced).

Roles: Only Owners, Managers, and Editors can process a dataset using the AutoGCPs in PIX4Dcloud.

Image and GCP requirements

Images:

  • Must be high quality; blurry or low-contrast images may cause detection failure.

  • Geolocated in WGS84 (EPSG:4326).

  • Geolocation accuracy: ≤5 m horizontal, ≤10 m vertical.

  • Captured at nadir or slightly oblique angles.

GCPs/CPs:

  • Supported target types: squared, diagonal, and Aeropoints.

  • Recommended size: ≥20× average GSD of the project.

    • Example: GSD = 2.5 cm → target ≥50 cm.

  • Black and white targets preferred; other colors may work under specific conditions.

  • Minimum distance between points: 15 m.

  • Must have a projected coordinate system.

targets.png

Warnings:

  • At least 3 GCPs must be detected.

  • AutoGCPs can search within a 5×5 m range of the coordinates specified in the CSV; large inaccuracies may prevent detection.

  • If detection fails, GCPs/CPs will not be considered during processing.

Upload the GCPs/CPs file

  • Create a new dataset and navigate to Step 4: GCPs automation.

  • Click Upload file and select the CSV containing GCP/CP details.

  • Optional:

    • Replace the file: Replace file.

    • Delete the file: Delete. delete.png


CSV format file

Column Required Description
1 Yes Label
2 No Type (GCP or CHECKPOINT, default: GCP)
3 Yes X coordinate
4 Yes Y coordinate
5 Yes Z coordinate
6 No XY accuracy
7 Cond. Z accuracy (required if column 6 defined)
 
Example: File with 5 GCPs and 1 Checkpoint in projected coordinates without accuracy values. 
001_,GCP,4392829.089,5386534.037,424.524
002_,GCP,4392772.823,5386545.0894,424.582
003_,GCP,4392732.981,5386516.197,424.723
004_,CHECKPOINT,4392761.505,5386468.789,422.646
005_,GCP,4392755.707,5386431.546,426.298
006_,GCP,4392832.252,5386456.906,427.001

Defining the GCPs/CPs coordinate system

  • Upload a PRJ file or search for a coordinate system by EPSG code or name.

    • GCPs_crs_definition_v2

  • Only projected coordinate systems are supported.

    • GCPs_crs_definition_v2

Warning: The GCP/CP coordinate system must match the output coordinate system. Selecting a different coordinate system will overwrite the previously defined output system.

Viewing and editing control points

  1. Click See and edit control points to open the Control Points Table (Step 5: GCP automation).

Control Points Table Features:

  • Verify imported coordinates.

  • Change the type of a point (GCP ↔ Checkpoint).

  • Swap Easting and Northing if values are inverted.
    Table GCPs PIX4Dcloud

Control Points Map:

  • Displays GCPs and CPs on a background map.

  • Verify that points are at expected locations. Incorrect positioning indicates coordinate or CSV issues.

  • Optional: switch a point between GCP and CP.

  • Save changes as needed.


Images and GCPs are in the same coordinate system Images and GCPs are not in the same coordinate system

Warning: GCP/CP detection fails if the output and GCP coordinate systems differ.

Start processing

  • Click Process to upload input files and start processing.

  • AutoGCPs detection runs automatically.

    • If GCPs are not found, an email is sent notifying the user that processing will continue without them.

  • Upon completion, a Quality Report is emailed.

  • In Files > GCPs, successfully detected points are displayed with their details.