ONeill Presentation

Airborne LiDAR in Ordnance Survey Ireland

Valerie O’Neill

Ordnance Survey Ireland;

Airborne LiDAR has been in use in OSI since 2005. A Leica ALS50 phase2 is the current system in operation. The system is 150 hertz (max 150 returns per second), incorporates MPIA (multiple pulse in air) and is capable of up to 4 returns from each pulse). The system is mounted in a light aircraft on standby all year round in Shannon awaiting suitable weather conditions. The trajectories of the flight-lines and Geo-referenced point-cloud are processed using Leica GrafNav Software & ALS Post Prosessor software. The point-cloud can be classified/filtered into individual layers such as ground, buildings, vegetation using the TerraSolid suite of software. DTM and DSMs outputted from this filtered data have many different applications including noise mapping, flood mapping, road re-alignment and route planning. All OSI LiDAR datasets are verified using ground truthing by GPS and the accuracy of 2m DTM is +/- 25cm. Approximatly 20% of the landmass of Ireland is currently covered by LiDAR data. The average point density (hits on target) of the data captured to date is approximately 1-2 pts per m sq. A maximum point density from this system mounted in a fixed wing aircraft, minimum flying height of 700m is approximately 10-12 pts per m. sq.

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