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

This article provides step-by-step instructions for importing and marking ground control points (GCPs) in PIX4Dcatch. PIX4Dcatch supports collecting, importing, and marking GCPs.

IN THIS ARTICLE

Point Collection
Measure GCPs
Import GCPs to PIX4Dcatch
Mark GCPs in a PIX4Dcatch project
Processing projects with GCPs

Point Collection

A ground control point (GCP) is a point with known coordinates. Their coordinates have been measured using reliable surveying methods or obtained from other sources (LiDAR, older area maps, Web Map Service). GCPs are used to georeference a project. For more information about Point Collections, click here.

 

Measure GCPs

GCPs can be measured using PIX4Dcatch when paired with a supported RTK device.

Tip: Take reference images and add descriptions when measuring your GCPs. This detail will make it much easier to mark the correct points in the images later.

Import GCPs to PIX4Dcatch

PIX4Dcatch allows the import of existing GCPs and the creation or updating of a Point Collection.

Important: If importing to an existing collection, it must use the same coordinate reference system

 Here's the instruction on importing GCPs to an existing point collection

  1. On the PIX4Dcatch home screen, tap Survey at the bottom.

    box survey

  2. Select the desired Point Collection.
    Plantilla Iphone (40)
  3. Tap the tree dots icon 9910856599453-2 in the top right and select Import.
    import box 
  4. Select the file to be imported.
    import

Here's the instruction on importing GCPs as a Point Collection:

  1. On the PIX4Dcatch home screen, tap Survey at the bottom.

    box survey

  2. Tap + New at the bottom.
    Plantilla Iphone (40)-1
  3. Fill in the name and select Import Coordinate System.
    importar

  4. Tap Import file and select the file.
  5. Tap Create in the top-right corner.
    createeee

Mark GCPs in a PIX4Dcatch project

To mark GCPs in a project, the Point Collection must first be assigned to the project. Then, the GCPs must be manually marked on the corresponding images. For more information: How to use automatic Tag Detection and manual GCP marking - PIX4Dcatch RTK.

Processing project with GCPs

Once GCPs are marked on the images, the project can be processed to improve accuracy. For more information: Processing projects - PIX4Dcatch.