How to import the custom coordinate system in PIX4Dcatch

PIX4Dcatch provides a large catalog of predefined coordinate reference systems (CRS). If the required system is not available or you need to use a custom or unsupported system, you can import a custom CRS using a Well-Known Text (WKT) file.

A WKT file is a plain-text file that defines all the parameters of a Coordinate Reference System. PIX4Dcatch supports both WKT1 and WKT2 formats, allowing you to use custom coordinate systems as well as Site Localization files.

PIX4D also provides a Site Localization Calculator through your PIX4D account. This tool allows you to create Site Localization files compatible with PIX4Dmatic, PIX4Dcloud, PIX4Dcatch, and third-party applications. More information about Site Localization files is available here.

 WKT File Requirements & Formatting 

To ensure PIX4Dcatch successfully recognizes and applies your custom coordinate system, your file must adhere to the OGC Well-Known Text for Coordinate Reference Systems standard and meet the following criteria:

• Projected CRS: The file must define a projected Coordinate Reference System.
• Recognized Geoid: If a Geoid Model is included, it must be recognized by the PIX4D database.
• No Invalid Combinations: You cannot combine an EPSG Vertical CRS with a custom or constant geoid height.

 How to Import a WKT File 

You can import a WKT file into PIX4Dcatch at three different stages: uploading a project, creating a new point collection, or when defining project settings. 

1. During the upload of the project to the cloud for processing.

By default, PIX4Dcatch uses the automatically detected CRS during upload. This can be overridden by importing a WKT file.

To use the WKT when uploading to PIX4Dcloud, follow these steps:

1. Tap the Upload icon to upload the project to the PIX4Dcloud. 

2. The Cloud Processing Option will be displayed. Tap Output coordinate reference system. 

3. Tap Import WTK file under Import Coordinate System.

4. Tap Import file and select the WKT file.

5. The file will be shown as imported Coordinate System.

6. Tap Select. If the import is successful, the WKT file name will replace “Auto Detected.
   
   

During the Point Collection 

When starting a new point collection, the output CRS can be selected from the catalog or imported from a WKT file.

To insert a WKT when creating a new point collection, follow these steps:

1. Tap Survey icon located on the lower right of your screen.
   
2. Tap + New to create a new point collection.
3. Name the Point Collection.
   
   
4. Select Import Coordinate System.
5. Tap Import File and select the WKT file. The file will be shown as the imported Coordinate System.
6. Tap Create.

Updating it using the Project Settings

The CRS can also be updated in project settings from the PIX4Dcatch app's home screen.

To use the WKT in the project settings, follow these steps:

1.  Tap the User icon located on the top right corner of the main screen.   
2. Under Settings, tap on Project Settings.
3. Tap on Output coordinate reference system.
4. Tap Import Coordinate System
   
5. Tap Import file and select the WKT file. The file will be shown as imported Coordinate System.
   
   

6. The file will be shown as imported Coordinate System.

7. Tap Select

If the import is successful, the WKT file name will replace “Autodetected.”