Buying a building plot in or around Port Glasgow? See how the ground falls and what constraints apply before you commit, using the Scottish Government LiDAR flown over the area and published on the Scottish Remote Sensing Portal.
Across the Port Glasgow area (18.6 km² from the OS Open Names extent), open LiDAR covers 82.4% of the ground. The best survey for most of it is LiDAR for Scotland Phase 6, flown 2022 on a 0.5 m grid (76.4% of the area).
Other parts use LiDAR for Scotland Phase 3, flown 2015–2019 (5%); LiDAR for Scotland Phase 5, flown 2021 (0.6%); LiDAR for Scotland Phase 2 (DTM only), flown 2012–2014 (0.2%); LiDAR for Scotland Phase 1, flown 2011–2012 (0.2%). A plot near the join between surveys may draw on both; the report shows which survey covers each part of your boundary.
That survey is recent (about 4 years old), but anything built or dug since still won't show. The flight date is on every page of the report.
Most of the ground across the area (96% of readings) lies between -0.4 m and 236.5 m above Ordnance Datum, with a median of 96.2 m. The extremes (-11.1 m to 261.8 m) can include water surfaces and data edges, so we don't quote them as ground levels.
That makes Port Glasgow steep ground by Scottish town standards: about a quarter or more of it falls faster than 1 in 10. On slopes like that, the cut-and-fill estimate and the fall across the plot are often the numbers that change a build budget most, so they're worth seeing before an offer.
Parts of the area are less than 5 m above Ordnance Datum, so a plot report here also lists whether SEPA's mapped flood extents touch the boundary. That is a map layer, not a flood risk assessment.
Fitting a plane through the 10 m levels, the ground across Port Glasgow falls generally towards the north at about 80.5 m per km (roughly 1 in 12). The lowest tenth of the ground lies mostly to the north, and the highest tenth lies mostly to the south-west.
About 29% of the 10 m samples are flatter than 1 in 40, while one in ten is steeper than 14.6°.
On SEPA's flood maps (medium likelihood), 1.2% of the Port Glasgow extent is inside the river flood extent, 6.9% inside the surface water extent and 37.3% inside the coastal extent. The extent is a rectangle round the town, so it can take in foreshore, sea and open ground. These are indicative national maps, not a flood risk assessment; a plot report gives the figures for your own boundary.
Historic Environment Scotland has 24 listed building records in the extent (4 category A, 13 category B, 7 category C), and 2 scheduled monuments overlapping it. A plot report lists any that touch or sit near your boundary.
NatureScot protected areas overlapping the extent: Inner Clyde (SSSI); Knocknairs Hill (SSSI); Inner Clyde (SPA); Inner Clyde (Ramsar site).
None of the Port Glasgow extent is within the Coal Authority's Development High Risk Area.
Nearest towns with pages here: Greenock, 4.5 km north-west, median ground about 49 m lower; Dumbarton, 7.8 km east, median ground about 88 m lower; Helensburgh, 8.2 km north, median ground about 66 m lower; Gourock, 8.6 km north-west, median ground about 39 m lower.
Sampled every 10 m, the typical slope is 4.2°, and 39.8% of the area is steeper than 1 in 10. A single plot can be much flatter or steeper than this. Its report works at 0.5 m.
| Area checked | 18.6 km² (OS Open Names extent, at most 6 km across) |
|---|---|
| LiDAR coverage | 82.4% |
| Best survey | LiDAR for Scotland Phase 6, flown 2022, 0.5 m grid (76.4%); typical ±0.13 m |
| Also used | LiDAR for Scotland Phase 3, flown 2015–2019, 0.5 m grid (5.0%); typical ±0.14 m |
| Also used | LiDAR for Scotland Phase 5, flown 2021, 0.5 m grid (0.6%); typical ±0.13 m |
| Also used | LiDAR for Scotland Phase 2 (DTM only), flown 2012–2014, 1.0 m grid (0.2%); typical ±0.15 m |
| Also used | LiDAR for Scotland Phase 1, flown 2011–2012, 1.000002600000007 m grid (0.2%); typical ±0.15 m |
| Ground levels | mostly -0.4–236.5 m AOD (2nd–98th percentile), median 96.2 m |
| Slope (10 m sample) | median 4.2°, 90th percentile 14.6°, 39.8% steeper than 1 in 10 |
| Overall fall | towards the north, about 80.5 m per km |
| SEPA flood maps (medium likelihood) | river 1.2%, surface water 6.9%, coastal 37.3% of the extent (awareness only, not a flood risk assessment) |
| HES records in extent | 24 listed buildings (A 4, B 13, C 7), 2 scheduled monuments, 0 conservation areas, 0 gardens and designed landscapes |
| NatureScot protected areas | 4 |
| Coal Authority high risk area | 0.0% of the extent |
Read from the open LiDAR at a 10 m sample on 2026-10-23; local data checked 2026-10-23. A plot report reads the same data at 0.5 m for your boundary only.
Accuracy. We test Scottish LiDAR against independent survey overlaps and Ordnance Survey levelled trig pillars: heights are ±0.14 m typical on open ground (95% within ±0.28 m). Results by survey phase.
Greenock · Dumbarton · Helensburgh · Gourock
Place names and extents: OS Open Names. Contains OS data © Crown copyright and database right 2026. LiDAR: contains Scottish Government LiDAR data, Open Government Licence v3. ©SEPA 2025; this SEPA product is licensed under the Open Government Licence version 3.0. Third-party data attribution statements: https://www.sepa.org.uk/media/5zidnja5/sepa_flood_maps_data_attribution_statements.pdf (SEPA flood maps are indicative and not suitable for individual properties). Contains Historic Environment Scotland and Ordnance Survey data © Historic Environment Scotland - Scottish Charity No. SC045925 © Crown copyright and database right 2026. Open Government Licence v3. Contains NatureScot information licensed under the Open Government Licence v3. Contains Mining Remediation Authority (formerly the Coal Authority) data, Open Government Licence v3. See data licences.