When using PPK corrections for a drone survey, your corrected camera positions are often available in a .csv file that is separate from your drone photos. In this article we'll show you how to properly format your .csv/.txt file so that you can add your drone photos, along with their accurate camera positions, directly to your Terrain Creator project.


Note: You can also Add Photos by selecting JPEG files, but the camera positions should be available in the Exif information. This option is mostly used with GPS or RTK geotagged photos.



Overview


Minimum CSV Format to Include Drone Photos

At a minimum, your .csv file needs to include proper column headers, the JPEG file names, and the PPK camera position coordinates. Terrain Creator will ask you to set the Project Coordinate System once you've added the .csv/.txt file.


The proper format for your .csv/.txt files includes the following headers:

  • Image - JPEG file name
  • Y - Northing/Southing/Latitude of the camera position 
  • X - Easting/Westing/Longitude of the camera position
  • Z - Elevation of the camera position


Important: At the very least, you need to keep your .csv/.txt file in the same folder as all your referenced photos. This is the simplest way to set up and organize your files. If you would like to organize your drone photos separately from your .csv file, see the Tips & Tricks section of this article.



Option to Add the Project Coordinate System

If you'd like to tell Terrain Creator what coordinate system your camera positions are in when you add the drone photos, you can include an EPSG code for both the horizontal coordinates and a vertical reference. If you don't include the EPSG code in your .csv/.txt file, Terrain Creator will simply ask you to set a project coordinate system after you add the file to your project.


Note: If the PPK camera positions are in the 4326 (WGS84) coordinate system, Terrain Creator will ask you to set a projected Project Coordinate System.


To add the EPSG code, just include it in the first row of your list, preceded by the # symbol:

  • #EPSG: horizontal coordinate+vertical reference


In the example above, 7855 represents the horizontal coordinate system for Australia (GDA2020 / MG zone 55) and 5711 represents the vertical reference for Australia (AHD height).


Option to Add Camera Position Accuracy

You can add camera position accuracies to each photo by including headers labeled xy accuracy and z accuracy directly after the image and x, y, z camera position headers. If the xy accuracy and z accuracy headers are not included in the .csv file, Terrain Creator will assume an RTK/PPK horizontal camera accuracy of 2 cm and a vertical camera accuracy of 4 cm:


Column headers: 

  • Image - JPEG file name
  • Y - Northing/Southing/Latitude of the camera position
  • X - Easting/Westing/Longitude of the camera position
  • Z - Elevation of the camera positions
  • XY accuracy - Horizontal camera accuracy
  • Z accuracy - Vertical camera accuracy


Add Drone Photos to Your Project

When you are ready to add your drone photos with a .csv/.txt file, start a new project in Terrain Creator:

  1. Click Add Photos>From txt/csv. 
  2. Select the .csv/.txt file that includes your drone photos (JPEGs).
    1. Follow the minimum .csv formatting requirements to include your photos.
  3. Enter your Project Coordinate System and Vertical Reference.



Your drone photos are now added to the Terrain Creator project with the appropriate PPK camera positions.



Note: If you initially added photos as JPEGs but would like to use PPK camera positions from a .csv file instead, you will need to remove all those photos and add them back in using the Add Photos>from .csv/.txt option.



Tips & Tricks

  • A great way to organize your photos and .csv file is by placing your drone photos in a subfolder from the folder your .csv/.txt file is in, e.g.:

    When referencing drone photos in a subfolder, your .csv file will need to include the file directory subfolder name before the drone photo file names: