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18. Surveying of buildings

When and why do we need to survey buildings?

  • as-built plan
  • reconstruction needs to be planned and the original plans are not available or not up-to-date - an example: an old floor plan with poor quality
  • condominium establishment
  • heritage preservation

Classic method (less frequent nowadays): floorplansection, facade are developed independent 2D drawings

Modern method: 3D surveying as well as modelling, 2D drawings can be generated

Simple method:

  • using a steel tape and/or Laser Distance Meter to measure distances
  • using a sketch to record data - an example
  • using an appropriate app on a smart device with Bluetooth connection -, for instance
  • good and efficient for a simple flat, drawing is developed in a local system
  • result: floorplan - an example (compare to the sketch above)

More modern method - total station:

  • reference points in the building in the same system
  • some detail points measured by tacheometry (total station) - an example
  • significance of digital images taken by a total station - an example: points to measure, generated by an architect, this photo shows the points that a land surveyor has to measure, coordinate list: this is the first result of surveying, images taken by the total station of each point:  image1image2, ...
  • further details by tape and/or Laser Distance Meter
  • result: 3D wireframe model at different levels in a local or national system - an example

More modern method - terrestrial laser scanning,

  • several stations, registration into the given system using and measuring targets
  • result: 3D point cloud or 3D solid model - an example

More modern method - mobile mapping -


  • the instrument is in hand, in a backpack
  • sensors are on a vehicle, like Google Streetview
  • efficient, impressive but less accurate (at the moment)

Another modern method - (digital) photogrammetry

  • terrestrial: images are taken from a camera
  • arial: images are taken from a drone
  • overlapping images, registration, relative, transformation into a given system using reference points measured by total station, professional software is required, e.g. Regard, Agisopht, Recap, ...
  • result: 3D point cloud or 3D solid model with texture
  • an example: image1, image2, image3, image4, image5, coordinate list of reference points, point cloud generated from the pictures using Regard3D

Steps of processing:

  1. take pictures, at least 80% overlapping
  2. add pictures
  3. compute matches, et keypoints (~10k in the example above)
  4. triangulation
  5. pointcloud (~48k)
  6. dense point cloud (~500k)
  7. georeferencing: using reference points measured by the total station in order to transform the model into a given reference system
  8. export point cloud