After having measured photo control for aerial photography since 20 years, it was a welcome change to be asked to provide the control network for a flight mission in Belfast.

We have surveyed 1000’s of photo-control points along various railway, water pipeline and road corridors, most notably the Thames Crossing several times. The company has been involved in South Wales railways, Oxford to Bedford and Aylesbury, East Coast Mainline and anything between Edinburgh and Glasgow.

This project was different, as the resulting mapping was going to be used for flood plain mapping and tidal flood prevention. We sent 2 staff, and due to the work being weather depended, we could not take the risk with using the ferry. The plane at short notice to catch a weather window and 4 days of surveying in central Belfast and the Titanic Quarter saw us measure all the photo control points. Most of the points were re-observed to prove the accuracy achieved and all data processed in the office to get the required various Irish coordinates in different systems. A week after instruction, the client started the aero-triangulation to produce the mapping products for a swift turnaround.


  • Coordinate listing of photo-control points surveyed
  • Calculation and analysis of accuracies and differences
  • Pre-marked photo-control points painted in open areas
  • Additional detail points nearby to compensate for lost points