Ground Control Points — Installation Guide
Why GCPs matter
Ground Control Points (GCPs) are surveyed markers with known coordinates. They ensure aerial imagery and processed data are correctly georeferenced, aligning measurements with design drawings. Ground Control Points allow us to guarantee the absolute accuracy of the
deliverables and therefore the overall accuracy of the construction process
against the “As-Built” Drawings of the site. By using Ground Control Points,
all of the deliverables and information gathered is of much greater quality and
can be used as a “known-truth”.
Components needed
- Treated wooden stake (min 30×30mm, 300mm length)
- Screws and washers, corner pegs
- Target board (400×400mm Correx recommended)
Installation steps
- Review suggested GCP locations from KMZ/CAD and adjust as needed within the project boundary.
- Hammer stake into the ground.
- Fix target above the stake using screws and washers.
- Add corner pegs if required.
- Survey centre-point with GNSS rover or total station.
Tip: Drop targets at agreed locations first, then return with stakes and screws.
How many GCPs?
| Site area | Minimum GCPs |
|---|
| < 10 ha | 5 |
| < 50 ha | 9 |
| < 100 ha | 12 |
| < 200 ha | 19 |
| < 500 ha | 33 |
Best practice
- Protect each GCP with cones or tape (3×3m zone).
- Replace damaged GCPs immediately to maintain accuracy.
- Client is responsible for installation, maintenance and safety measures.
Related Articles
Flight & Camera Parametres for a Thermographic Inspection
This guide applies to the following sensor/drones mentioned in the Approved cameras & drones document. We divide each solar farm into 'Zones' for the purposed of flight planning and data transfer. These are the areas that you will map at a specified ...
Approved cameras & drones - Topographical and Construction Management
The following list for Topographical and Construction management imagery: Topographical mapping - Photogrammetry Multi Rotor ✅ DJI Matrice 4E ✅ DJI Mavic 3 Enterprise + RTK module ✅ DJI Mavic 3 Multispectral (RGB camera) + RTK module ✅ DJI ...
Introduction to GIS and Coordinate Systems
The Basics A coordinate system is defined in geometry as a system that uses one or more numbers, coordinates, to determine the position of the points. Unique values will have unique positions. The simplest example of this is the identification of ...