PPK Processing for Photogrammetry Snapshot Import

Overview

Post-Processed Kinematic (PPK) improves the accuracy of image geotags by correcting them after the flight using GNSS base station data.

In Sodex, PPK is available as a beta step inside the Snapshot Import wizard when you use Sodex cloud processing.

During PPK, Sodex updates your images’ EXIF GPS coordinates with corrected positions. The photogrammetry job then uses those corrected positions for processing.

Before you begin

Requirements

• Processing provider must be set to Processing by Sodex.
  The PPK step is only shown when Sodex is selected as the processing provider.

What you need (files + base coordinates)

Prepare the required GNSS files:

• Rover observation file 
• Base observation file 
• Base navigation file
• Image timestamp/marker file

You will also need the base station coordinates:

• Latitude / Longitude (WGS84, degrees)
• Height (meters, ellipsoidal height)

Step 1: File selection

1. Open the Snapshot Import wizard.
2. In File type, select Image data.
3. Click Images folder (folder icon) and select the directory containing your snapshot photos.
4. Optional: Enable Create pins from images to create map pins at the image GPS positions.
5. Click Next.

Step 2: Processing settings

In Processing Settings:

1. Provider: Select Processing by Sodex.
   This is required, otherwise the PPK step will not appear.
2. Configure the processing options as needed:
   • Point Cloud Precision (Low / Medium / High)
     Higher precision increases processing time, size and credit usage.
   • Point Cloud Density (Low / Medium / High)
     Higher density captures more detail, with higher processing cost, file size and processing time.
   • Orthophoto Resolution (cm/pixel)
     Smaller values produce higher detail and larger file size.
3. Review the cost estimate.
4. Click Next to continue.

Step 3: PPK settings

In PPK Settings, upload the GNSS files and enter the base coordinates.

Upload files

• Rover Obs: Rover observation file (drone GNSS log, RINEX .obs / .o)
• Base Obs: Base station observation file (RINEX .obs / .o)
• Base Nav: Navigation file (RINEX .nav / .n)
• Image Timestamps: Timestamp/marker file (commonly .mrk from the drone)

Enter base station position

• Latitude / Longitude: degrees 
• Height: meters 

When all required fields are complete, Next becomes available. Click Next to continue.

Step 4: Ground Control Points (optional)

If you have surveyed Ground Control Points (GCPs), you can add them.

1. Set Ground control points source to Custom (choose None to skip).
2. Enter Diagonal length (the physical size of your target marker).
3. Upload your CSV file with GCP coordinates.
4. Set:
   • Delimiter (Comma / Semicolon / Tab / Space)
   • Header row (Yes/No)
   • File unit (Meter / Foot / US survey feet)
5. Click Next.

Step 5: Snapshot metadata

Fill in the snapshot details:

• Name (required): Use a clear name.
• Description (optional): Notes about the capture.
• Get creation date from images:
  When enabled, the creation date is taken from the images’ timestamps.
• Creation date:
  Auto-filled if the option above is enabled; otherwise set manually.
• Point insertion option:
  Choose how the point cloud is positioned/aligned (default: Lowest point).
• Tags (optional): Useful for filtering later.

Click Import snapshot to upload and start processing.