Michael Gallie & Partners specialise in measured building surveys using laser scanning surveys for the whole measurement process. Below is an outline guide of our process of producing a laser scanning survey.
THE PROCESS
1.0 Survey Control Framework & Grid/Datum Setup
All our laser scanning surveys are based upon an accurate survey control framework using the latest survey equipment in the market. To relate the survey to Ordnance Survey national grid and datum our surveyors use 2 No. high accuracy GPS receivers on-site simultaneously for a 2-hour period.
2.0 On-Site Laser Scanning
At Michael Gallie & Partners, we only use laser scanning for all our measured building surveys. All areas of the building are fully laser scanned using the latest laser scanners on the market to ensure complete coverage. This involves a surveyor with a laser scanner mounted on a camera tripod carrying out multiple static setup positions across each floor typically for 1-2 minutes at a time. For some types of survey, we sometimes use a mobile hand-held laser scanner on-site for rapid but less accurate data collection. If you require a colour/RGB point cloud the site time for each static setup increases by at least 1 minute per setup. Mobile hand-held devices can take imagery simultaneously with the point cloud.
3.0 Laser Scanning Office Processing to Produce Point Cloud
Using specialist software and high-end specification computers, the laser scan survey is then processed and registered to the relevant site grid & datum. The resultant registered point cloud is checked, verified and exported in manageable floor by floor chunks ready for the CAD & 3D modelling process. Where required we also export the HDR colour/Greyscale images and/or point cloud taken by the laser scanner to create a TruView of each setup position carried out on-site. TruView is a web-based viewer software that documents the whole site conditions using measurable 360° pano-tour images taken from the laser scanner, an especially useful tool during the Covid-19 lockdown restrictions.
4.0 2D CAD & 3D Model Production
The laser scanning survey is then imported into either CAD for 2D deliverables or a BIM authoring software i.e. Revit ready for the modelling process. Our CAD & modelling teams work collaboratively together to avoid any repetition or modelling errors occurring. On each project the CAD & modelling team generally each work separately on different floors of the building and then synchronise back to the central model at suitable modelling milestones.
5.0 Client Issue
All laser scanning survey deliverables are issued to the client via a weblink download..
If you need any advice on commissioning a laser scanning survey, please contact Sam Lloyd at Michael Gallie & Partners who will be happy to assist you in this matter.