Palace Place, Brighton

We were asked by architects working for Brighton & Hove County Council (BHCC) to conduct a full measured building survey and to produce floor plans, a roof plan, and elevation drawings for Palace Place, an unused (at the time) building located beside the Royal Pavilion in Brighton.

Challenges

Access to the roof was difficult due to an unusable roof hatch and limited access around the building’s exterior. We decided to survey the area with a drone and use aerial photographs to create a photogrammetric model.

While planning the drone survey we noted that some nearby trees could hinder our piloting visibility and that potential landing areas were limited due to the roads around the property. Liaising with BHCC, we were given permission to use the Pavilion Lawns as our take-off point, giving us a more controlled environment to work from and a better vantage point from which to monitor the drone’s flight path over the building.

In the interest of public safety, several contingencies were planned to allow for situations where a member of the public might enter the drone’s flight path, including ‘holding areas’ (safe places to move the drone to mid-flight) and emergency landing areas. We also ensured clear protocols were in place for any emergency incident that might occur, such as pilot incapacitation (in which case the drone would automatically return to its designated landing area).

Methodology

Site control was established using our high accuracy GNSS receiver and a traverse loop around the building. We recorded several checkerboard targets and reference objects for use with the scan data and photogrammetry.

The interior and lower exterior of the building were scanned with our GeoSLAM Horizon scanner. The fact that the building was empty was most beneficial, allowing us to move quickly and efficiently with minimal scan distortion or noise from furniture or people.

As mentioned, we surveyed the roof using our DJI Mini 2, taking photographs from both a bird’s-eye and oblique view before stitching them together into a colourised point cloud.

The data we gathered was then collated and aligned to match the topographic survey’s control network before being digitised into the finished floorplans and elevations using GeoSLAM Draw and AutoCAD.