Pix4D Documentation

PIX4Dmatic

Getting started

Quick Start Guide - PIX4Dmatic

This article is a quick start guide on how to use PIX4Dmatic for the first time. In particular, this page will show how to get from an image dataset captured by a drone or PIX4Dcatch RTK to the creation of accurate 2D and 3D maps and models.

IN THIS ARTICLE

Setting up a project

LogIn Log in
Create_new_project Create new project
tie_points Import Tie points
coordinate_system Coordinate Reference System
image-outline Image Coordinate Reference system
GCPs Coordinate Reference System
project Project coordinate system

Processing options

Calibration
point_cloud Dense point cloud
mesh Mesh
dsm DSM
Orthomosaic

Outputs

folder-outline Locate the export folder

Video tutorials

Introduction to the PIX4Dmatic interface	How to process aerial imagery with PIX4Dmatic
How to process PIX4Dcatch data with PIX4Dmatic

Setting up a project

The first step in PIX4Dmatic is setting up the project, defining the required parameters, and adding the necessary data before moving on to processing.

Log in

Sign-up for a Pix4D account or use the existing Pix4D account to log in to the software.

Click icon or Log in on the top right side of the screen.
Enter the Email and click Continue.
Enter the Password and click Log in.

Important: Without a trial or a commercial license, the functionalities of the software are limited. For example, without a license, it is not possible to export results and save projects.

Note: Customers of organizations with a single sign-on (SSO) active subscription will be redirected to their organization webpage for SSO login after inserting their email address. If you are interested in activating the SSO login for your organization, please contact us.

Create new project

New projects in PIX4Dmatic can be created by dragging and dropping images or image folders on the home screen, using the menu bar, or the Ctrl + N (⌘ + N) shortcut.

Drag and drop input files

Drag and drop images or image folders on the home screen.
Specify the Project name, the Path of the project and the project Coordinate reference system (CRS).
Click Start.

A new project has been created and is ready for processing. To import additional input files use the File menu on the top left or drag and drop them on the screen.

For more information: Create a project - PIX4Dmatic

Import Tie points (GCPs and CPs)

Adding and marking Tie points (Ground control points (GCPs) and Checkpoints (CPs)) in a project is optional but it's a method to maintain and verify the absolute accuracy of a project.

For more information on Tie points: Tie points - PIX4Dmatic

For more information on how to mark Tie points: Mark Tie points - PIX4Dmatic

There are three methods to import a tie point .csv/.txt file into PIX4Dmatic. One is accessible through the File tab in the main header, and the others are accessible from the Tie Points panel.

[1] Go to the Menu bar and select File > Import > GCPs... to select the GCP file.
Click the Tie points (0) tab on the lower right of the screen to expand the tab.
[2] Drag and drop the GCP file, or Select from disk to specify the GCP file.
[3]Click the dropdown menu and select Import GCPs...
Select the tie point file.

Tie points can be imported and marked at different stages:

Before the Calibration step: This requires more manual work as the position of Tie Points on images is not precise as it is determined only based on the initial image geolocation and orientation. However, marking the Tie Points before processing can eliminate the need for reprocessing or reoptimizing the Calibrate step.
After the Calibration step: The position of Tie Points on images is more precise as external and internal camera parameters are calculated. However, you will need to reprocess or reoptimize the Calibrate step.

Coordinate Reference System

After importing the images and the Tie points, the Coordinate Reference System (CRS) must be set. PIX4Dmatic allows setting the CRS of the Images, the GCPs, and the Project.

Image coordinate reference system

PIX4Dmatic allows the image coordinate system to be manually set or edited.

To edit the image horizontal or vertical coordinate systems, click on the edit icon in the lower right corner of the screen where the Cameras tab is.

After clicking on the edit icon, the Set image coordinate reference system (CRS) dialog box will open.

Unless a camera is in the PIX4Dmatic camera database or the images have the correct XMP tags, the default image coordinate system is WGS84 (EPSG: 4326) for the horizontal and EGM96 (EPSG: 5773) for the vertical.

Warning: For PPK or RTK-enabled drones, it is advised to understand what coordinate reference system the images were acquired in. NTRIP networks or base stations may broadcast corrections on something other than PIX4Dmatic's default CRS, and this coordinate system should be set accordingly. Otherwise, an incorrect transformation will occur, and a shift in the outputs may result.

GCPs coordinate reference system

Both the horizontal coordinate system and the vertical coordinate system can be defined in the Tie Points table:

The GCP coordinate reference system (CRS) window will pop up.

To select the horizontal coordinate reference system:

In the Horizontal coordinate reference system dialog, search or copy-paste:
- The name or
- The EPSG code of the coordinate system.

To select the vertical coordinate reference system:

In the Vertical coordinate reference system dialog, search or copy-paste:
- The name or
- The EPSG code of the coordinate system.
(Optional) Geoid: If the selected vertical coordinate system supports geoids and the geoid model is available in the PIX4Dmatic database, select the geoid model in the drop-down list.
(Optional) Geoid height: If the selected vertical coordinate system supports geoids but the geoid model is not available in the PIX4Dmatic database, enter the value of the geoid height at that location.

For more information and the list of supported geoids, please see How to use Geoids in PIX4Dmatic.

Project coordinate reference system

The project Coordinate Reference System is derived from the GCPs coordinate system. No GCPs are required to change the coordinate system in a PIX4Dmatic project.

The horizontal and vertical coordinate reference systems of the project are defined based on the imported image geolocation data or the selected GCPs coordinate reference system:

The project coordinate system is always visible on the bottom bar:

When the GCPs coordinate system is not defined, PIX4Dmatic will default the project coordinate system to the corresponding UTM zone based on the position of the image geolocation. The vertical coordinate system is set to ellipsoidal heights*.

When GCPs coordinate system is defined, the project coordinate system corresponds to the GCPs coordinate systems. If the GCPs coordinate system is geographic the corresponding UTM zone is used for the project coordinate system.

Processing options

After setting up the project, the next step is processing it. From Calibrating the images to generating a Digital Surface Model (DSM) or an Orthomosaic, PIX4Dmatic has plenty of different options in each of the processing steps to choose from, depending on the project's needs. PIX4Dmatic comes with three different preset processing templates:

Nadir
Oblique
PIX4Dcatch

In addition to the default processing templates, it is possible to create custom processing templates that allow for predefined project settings to be saved, reused, and shared. For more information: Custom Processing templates - PIX4Dmatic.

Calibration

Calibration is the first step in processing a dataset and lays the foundation for the following steps. Default settings are provided and are generally the best place to start.

For more information: Calibration - PIX4Dmatic

For PIX4Dcatch projects: How to process PIX4Dcatch datasets - PIX4Dmatic

Dense point cloud

A dense point cloud is a series of dots spread across a volume of 3D space that represents the area of interest. The Dense point cloud step is a 3D representation of reality and it's the basis of the other 2D and 3D representations of reality that can be produced in PIX4Dmatic.

For more information: Dense point cloud - PIX4Dmatic

Image pre-processing

Image pre-processing: This processing step computes the required data to enable the object selection tool and it is a one-time requirement.

For more information: Object selection tool - PIX4Dmatic.

Mesh

The Mesh step is generated directly from the dense point cloud and is not necessary for every project. It is not required to generate a mesh to be able to generate the Digital Surface Model and the Orthomosaic.

For more information: Mesh - PIX4Dmatic

DSM

A Digital Surface Model (DSM) is a 2D representation of the elevation of everything in the area of
interest, both natural and artificial. The DSM step is required to generate the orthomosaic, so any
changes to the processing settings of the DSM will also impact the orthomosaic. The DSM step defines the Resolution, enables the Surface smoothing, and enables Interpolation for the Digital Surface Model (DSM) creation.

For more information: DSM - PIX4Dmatic

Orthomosaic

An Orthomosaic is a highly detailed and realistic 2D representation of reality generated by combining individual images. The Orthomosaic step is generated directly from the Digital Surface Model (DSM), so any errors or gaps in the DSM will also be present in the orthomosaic.

For more information: Orthomosaic - PIX4Dmatic

Outputs

Once processing is complete, the Exports window in PIX4Dmatic provides the selection of the following outputs:

Quality Report
Dense point cloud
Point cloud from mesh
Mesh
Digital Surface Model (DSM)
Orthomosaic

Locate the export folder

To access the outputs, click on File and then Open project folder. The exported outputs are in the Exports folder.

For more information: Outputs - PIX4Dmatic