A new project from A-Z - PIX4Dcatch RTK


PIX4Dcatch is an application available on iOS and Android for terrestrial photogrammetry. It utilizes available sensors in a mobile device (photo, LiDAR, IMU, GPS) while capturing data to create a 3D model.

The viDoc is a GNSS RTK receiver. It allows PIX4Dcatch to geolocate the images acquired by your mobile device with centimeter accuracy.

The data can be uploaded and processed on PIX4Dcloud to obtain 2D (orthophoto, DSM) and 3D (point cloud, mesh) results. Project data can also be exported and saved for processing using desktop software like PIX4Dmatic, and PIX4Dmapper.

This article describes the features and how to use the PIX4Dcatch application, connect to the viDoc RTK rover, capture a project, and process for the first time.

Basic requirements:
  • An Android or iOS smartphone or tablet compatible with the PIX4Dcatch application.
  • PIX4Dcatch app.
  • viDoc RTK rover.
  • An SP connect case compatible with your smartphone.
  • NTRIP service subscription or a GNSS base with NTRIP caster.
  • An Internet connection.
  • PIX4Dmapper, PIX4Dmatic, or PIX4Dcloud license for processing.
    (PIX4Dmapper does not support LiDAR data)

Install PIX4Dcatch

Mount the viDoc RTK rover to the Device

Connect PIX4Dcatch to the viDoc RTK rover

After the connection was initialized, you can proceed with the following steps:

PIX4Dcatch overview

The home/capture screen is the primary interface when opening the app. The signal quality tab and user account options button are found at the top of the screen.


PIX4Dcatch_signal_tab.png     Signal quality tab

PIX4Dcatch_signal_tab.png     The GPS quality tab is visible before connecting the viDoc RTK rover. Select the dropdown menu to connect to the viDoc RTK rover.

The RTK dialog


The PIX4Dcatch RTK dialog.

Once the viDoc RTK rover is successfully connected to PIX4Dcatch, the RTK dialog will be visible. This screen displays information that can be used to monitor the status of the connection and the resulting accuracies.

  • The header contains the RTK connection icon, satellite connections, battery level, and access to the RTK connection dialog.
    • Pix4Dcatch_ViDoc_RTK_fix_green The green RTK icon indicates the successful connection to the viDoc RTK rover.
    • 26  The number of satellites used in the RTK connection is indicated numerically. This number will vary in real time.
    • battery_full-outline  Battery level indicator.
    • arrow_downThe dropdown menu gives access to the RTK connection dialog.
  • RTK vertical and horizontal accuracy estimations.
    • Indicates the accuracy to which the viDoc RTK rover is expected to achieve. The unit of measurement is based on the mobile device's regional setting.
  • HDOP (Horizontal Dilution of Precision).
    • Indicates the current quality of the position and distribution of the satellites. Generally, the HDOP value is considered ideal below 1.
  • NTRIP RTK Status.
    • Indicates the type of RTK NTRIP connection.
      • RTK Fixed: Accuracy in the range of a few centimeters(in).
      • RTK Float: Accuracy in the range of 1m(3ft)
      • DGNSS Only: Accuracy in the range of up to 10m(32ft)
      • Autonomous GNSS fix: Accuracy in the range of more than 10m(32ft)
      • No Fix: The data is not valid, there are not enough satellites visible, or there are internet connection problems.

PIX4Dcatch_account_options.png     Account settings


PIX4Dcatch Account dialog.

Account details

  • Create Account: Access form for new users to create an account.
  • Log in: Access form for existing account holders to log in.


  • View Onboarding: View onboarding slides.
  • Documentation: Opens the PIX4Dcatch documentation page to access learning materials.
  • Community: Opens the PIX4Dcatch Community page.
  • Pix4D Terms and Policies: List of Pix4D terms and policies.
  • Third Party licenses: List of third-party licenses.
  • App Usage Disclaimer: Access the PIX4Dcatch App Usage Disclaimer.
  • The installed version of the PIX4Dcatch app.


PIX4Dcatch is ready to capture.

Capture functions and project folders are found at the bottom of the window. The capture button DARK.jpg starts a capture, and the pause button pause.jpg pauses a capture. During capture, the primary.jpg button saves a project, and the cancel_circle.jpg button aborts a project.

Live_preview_button.png     Live Preview


iOS and Android users who have LiDAR or ToF sensors in their devices can use the Live Preview feature to gain insight into what is being captured.

  • Map_view.png   Top view: Full view of the project area.
  • POV_view.png   First-person view: Focused view from the camera perspective.
  • Cancel_preview.png   Cancel: Close the Live Preview window.
  • point_cloud.png   Point Cloud: View the points collected.
  • camera_position.png   Cameras: Show the camera positions.

Use the live preview to help see what is captured.

file_blk.jpg     Projects


PIX4Dcatch Project dialog.

  • Search projects using keywords.
  • Filter projects by type.
    • Captured
    • Processed
    • Processing
    • All
  • The number of projects.
  • Select multiple projects for deletion.

Each project thumbnail contains unique information, including the number of images, upload status, project name, and capture date. Tap and hold a project to access the project menu allowing further actions.


Project thumbnail menu.

  • Rename: Rename the project
  • Upload: Upload to PIX4Dcloud
  • Export all data: Export the entire project to save or process locally.
  • Export captured point cloud (PLY): Exports the collected point cloud from devices with LiDAR or TOF sensors. (This is not used in processing but for visualization in the Live Preview)
  • Export captured mesh (OBJ): Export the collected mesh when selected.
  • Export Logs: Exports the current log files documenting internal aspects of the entire project. It is important to export logs soon after a potential issue as they can be overwritten with new information.
  • Delete: Deletes the project.

GCP_management.png     Point management


PIX4Dcatch Point Management dialog.

From the Point Management dialog window, it is possible to:

  • See the number of collections.
  • PIX4Dcatch_GCP_list_map_view_toggle.png Toggle between list and map views.
  • List of existing collections.
    • coordinateSystem_icon.jpg Measurement coordinate reference system.
    • marker.png The number of measured points in the collection.
  • PIX4Dcatch_new_collection_button.jpg Start a New Collection.

Select a collection for the list of points measured.


PIX4Dcatch single point collection dialog.

  • export.jpg Export Point collection. Complete(full information) and PIX4Dmatic-based files(for direct import to PIX4Dmatic), along with logs, are exported.
  • Collection name.
  • The number of measured points currently in the collection.
  • PIX4Dcatch_GCP_list_map_view_toggle.png Toggle list and map views
  • Collected points.
    • PIX4Dcatch_single_point_card.jpg

      PIX4Dcatch single point measurement dialog.

    • Point name.
    • RTK/GPS tag.
    • Horizontal and vertical accuracies.
    • Coordinates measured.
    • calendar.png Date measured.
    • timer.png Measurement duration.
  • New_Point.png Measure a new point.
  • Output coordinate reference system for the Point collection.

settings_button.jpg     Settings


PIX4Dcatch main settings dialog.

Use the Settings dialog to adjust and customize features within the PIX4Dcatch app.

For detailed information: Settings - PIX4Dcatch.

Capture a project

Once the viDoc RTK rover is successfully connected to PIX4Dcatch, wait for RTK Fixed. The number in the upper left indicates the number of satellites used in the connection. For an optimal experience, make sure the antenna is not obstructed and that you have a good internet connection.

Example: After RTK fixed is established, the Horizontal Accuracy and Vertical Accuracy are in the range of a few centimeters. In ideal conditions, the values are close to 0.01m/0.03ft.


PIX4Dcatch RTK dialog.

The accuracy values can vary and depend on multiple factors, for example:

  • Blocked and reflected GNSS signal, close to buildings, trees, or bridges.
  • Rapid movements of the device.
  • Poor cellular reception.

For more information: GNSS and viDoc RTK rover best practices.

Processing a project

To process the data, you can use the following PIX4D software:

  • PIX4Dcloud / PIX4Dcloud Advanced. The fastest cloud-based solution for downloading, processing and sharing results. PIX4Dcloud can process LiDAR data.
  • PIX4Dmatic. Local solution, on PC or Mac. PIX4Dmatic can process LiDAR data.
  • PIX4Dmapper. Local solution on PC.

Export formats by software :

  • PIX4Dcloud / PIX4Dcloud Advanced: las, obj, tiff, dxf, csv, GeoJSON, shp.
  • PIX4Dmatic: laz, obj, tiff, etc.
  • PIX4Dmapper: las, obj, tiff, shp, dxf, mp4, pdf, etc.

PIX4Dcatch Settings

Advanced settings

Features available depend on the device used for capture. Please select the device make for detailed information.

Apple iPhone/iPad Advanced Settings

Capture Quality


PIX4Dcatch iOS Capture Quality settings

  • Warning Sounds: Receive audible warnings during capture.
  • Auto Focus: Sets the camera settings as autofocus.
  • Skip Low-Quality Images Will perform some checks if the device is moving too fast and will not take photos. A warning message is shown on the screen during the capture.
  • Resolution: Sets the resolution for the captured images. Resource dependency will increase with the selection of higher resolutions, including increased process times and extra storage requirements.


    PIX4Dcatch iOS Resolution settings

    • Normal: Lower than 4k*
    • 4K: Approx. 4K*
    • Maximum Resolution: above 4k*

* Depends on the device. Refer to the device specifications for more information.



PIX4Dcatch iOS View settings

  • Shown Cameras: Display the camera indicator (image pyramid) for each captured photo.
  • Show Feature Points: Display the feature points as detected by the device. More feature points mean better accuracy.



PIX4Dcatch iOS Mesh settings

  • Save Mesh: Save the Mesh OBJ file for export.
  • Enable Mesh: Generates a Mesh from LiDAR depth data. Available only for devices with LiDAR.
  • Mesh Settings: Set the mesh type and mesh colors.


    • Mesh Type
      • Mesh | Wireframe: Display the mesh or cameras as wireframes.
    • Mesh Color: Allows to adjust the color of the mesh and/or the camera indicators based on the provided color bands. The value ranges from 0 to 1.



PIX4Dcatch iOS Other settings

  • Save Video: A video of the capture session is saved.

Android Advanced Settings



PIX4Dcatch Android View settings

  • Shown Cameras: Display the camera indicator (image pyramid) for each captured photo.
  • Show Feature Points: Display the feature points as detected by the device. More feature points mean better accuracy.
  • Warning Sounds: Receive audible warnings during capture.

Mesh Color


PIX4Dcatch Android Mesh Color settings

Allows to adjust the color of the mesh and/or the camera indicators based on the provided color bands. The value ranges from 0 to 1.



PIX4Dcatch Android Other settings

  • Auto Focus: Sets the camera settings as autofocus.

Single Point Measurements

For an offline and printable version of this information: PIX4Dcatch & viDoc RTK rover Quick Start Guide.

Was this article helpful?
7 out of 8 found this helpful

Article feedback (for troubleshooting, post here instead)


Article is closed for comments.