Specialist
Biodiversity Net Gain Surveys
The survey evidence a Biodiversity Net Gain plan needs, gathered to the level the metric actually depends on. Habitat condition, species-richness indicators, bare ground, tree and scrub extent and the hydrology underneath, captured by air and ground so the ecologist and the metric assessor are working from measurements rather than a site visit and a guess.
Typical accuracy · Habitat boundaries from LiDAR and photogrammetry at roughly 5 to 10cm, with boundaries drawn to a defensible positional accuracy rather than a nominal figure. Peat depth from drone-based GPR is typically ±100mm where the ground allows a return from the peat interface; it is a measured depth at transect points, not a continuous model between them.
When you need it
- →A planning application needs a BNG assessment and the surveyor needs to feed it.
- →A 30-year plan is being secured and long-term management needs evidence to be written against.
- →Offsite habitat is being located and the unit value has to be defended.
- →You need condition monitoring on a fixed schedule, and the results have to be comparable each time.
What you get
- Habitat extent and condition mapped to a national classification
- Multispectral-derived vegetation indices by parcel, georeferenced and mapped
- LiDAR surface, canopy and ground point clouds where structure matters
- Drone-based GPR peat depth and condition transects, on peat and fen sites
- A repeatable baseline so later monitoring is a like-for-like comparison
How it runs
- 01
You send the site, the constraint map and what stage the plan is at.
- 02
We agree the survey boundary and which condition categories apply.
- 03
LiDAR, aerial and multispectral capture, with drone-based GPR where peat depth is in question.
- 04
Ground truth on the classifications the imagery cannot settle alone.
- 05
Handover as mapped data and a short written note on what is measured versus inferred.
- Horizontal control
- ±10mm typical
- Vertical control
- ±8mm typical
- Datum
- OSGB36 · EPSG:27700
- Area covered
- Norfolk base · 6 regions
Questions we get asked
Do you do the ecology as well as the survey?
No, and we would rather say so than blur it. We provide the measured survey and the spatial data an ecologist needs. The condition assessment, the species walk and the metric calculations sit with a competent ecologist, and the best projects have us and one working from the same data rather than two sets of assumptions.
Why does peat depth matter for BNG?
Because peat is a conditionally rare habitat, and its condition is judged on its structure and its hydrology. On fen and peat sites, drone-based GPR gives a measured depth and interface along transects, which is what tells you whether the ground is thin embanked mineral soil or deep peat. You cannot get that from a drone photograph.
Can you do baseline and 30-year monitoring on the same site?
Yes, and you should, because the value of monitoring is entirely in the comparison. The same flight lines, the same classification and the same GPR transects mean year three can be put against year zero directly. Repeatedly re-surveying with a slightly different setup produces numbers that cannot be compared, which is worse than not monitoring at all.
What resolution do the multispectral products come out at?
Far better than satellite, and fine enough to work a parcel rather than a whole field. The limit is usually the classification rather than the imagery, which is why we ground truth. We would rather hand you a small area confidently classified than a large area confidently misclassified.
Often needed alongside
LiDAR & 3D Laser Scanning
Millimetre-accurate point clouds that reach beneath vegetation.
Multispectral & Agricultural Survey
NDVI and NDRE analysis to reveal crop stress and irrigation issues.
Drainage & Flood Risk Surveys
Flood zone assessment and drainage run-off measurement.
Topographic & Land Surveys
Levels, contours and site detail for planning, design and construction.
Where we cover
Norfolk based, working nationwide. Site-based surveying, so distance is rarely the constraint.
Most requested in Norfolk, Suffolk, Cambridgeshire & Essex.
Every town, district and borough we cover is listed in full on each region page. See the full service area.
All 18 other services
Start here
Send the address and what it is for.
You will get a straight answer on whether this survey is the right one, and what it should cost. If it is not, we will say so.
info@prospaplans.com · Norfolk, Kent, London, East Anglia and the Midlands