Video imagery and flow measurements from five surveys on the River Tweed, July 2024-June 2025

This dataset contains river surface velocity data from video footage and from a kinematic current meter, during five surveys on the River Tweed in Scotland from July 2024 to June 2025. For the video footage, different Ground Control Point (GCP) positions and camera angles are adopted for a comparison of error from various image velocimetry techniques. The footage was captured using a nadir angle with a Unmanned Aerial System (UAS), as well as from an oblique view using an iPhone 14 Pro Max camera, with GCPs positioned at the free water surface and at an elevation above the free water surface. The footage frames were extracted and processed using three different image velocimetry softwares (Particle Tracking Velocimetry (PTV), Particle Image Velocimetry (PIV) and Space-Time Image Velocimetry (STIV)). Raw surface velocity outputs from the softwares are recorded herein.

The data also includes the extracted frames from the geometrically corrected image velocimetry frames (orthophotos) from the three different viewing angles, and values for tracer density from a preliminary analysis is also included. Discharge data was collated during the final survey in June 2025 using the velocity-area method and salt dilution gauging. This data is recorded alongside an estimation of discharge from image velocimetry surface velocity data using the trapezoidal area of the river.

The data was collated for the purpose of evaluating error propagation in image velocimetry applications under operational and sub-optimal environmental conditions. It was collected as part of a PhD project developed to assess the operational efficacy of image velocimetry applications in the UK. The data is complete and unfiltered.