Case Study

Update of Centennial Campus Digital Surface Model (DSM)


      • Centennial Campus (Textiles buildings), NCSU
      • acquired with DJI Inspire by NGAT
      • Camera model: FC350 (3.61mm)
      • 02/24/2018
      • 1 nadir flight, 4 oblique: 30 ° in the North, South, East, and West direction.

Flights area:

  • green dots represent camera stations
  • green lines represent flight paths
  • crosses indicate GCP and Check Points location

Overview of the area -

      • 3D model , limited extent

Processed data

      • Processing environment: Agisoft Photoscan Professional 1.4.1

Overview of the area -

      • orthophoto , full processing extent

Processing results without Ground Control Points

Processing report

                • Number of images: 248
                • Average flying altitude: 171 m
                • Ground resolution: 4.53 cm/pix
                • Coverage area: 0.166 km²
      • DSM: 18.1 cm/pix
      • orthophoto: 4.53 cm/pix
      • pointcloud: 30.4 points/m²
      • 3D model

Processing results with Ground Control Points

Processing report

          • Number of images: 389
          • Number of Ground Control Points: 7, Number of Check points: 4
          • Average flying altitude: 154 m
          • Coverage area: 0.114 km²
  • DSM: Ground resolution: 15.9 cm/pix
  • orthophoto: Ground resolution: 3.97 cm/pix
  • pointcloud: Point density: 39.7 points/m²
  • 3D model

Lidar-based DSM: original 2013 survey and after partial 2018 UAS data update:

The update added two new buildings and captured removal of trees in construction areas

The lidar DSM resolution is 1m (as compared with 15cm UAS DSM) and there was no fusion performed in this test.

Zoomed-in area of change

UAS DSM (15cm resolution, with draped orthophoto) that was used to update the lidar-based DSM, note that DSM does not include representation of facades as opposed to full 3D model shown above.

Comparison of UAS DSM with the official building footprints (white line)

Preliminary comparison with the 2015 lidar data: blue is elevation gained (e.g. new buildings), red is elevation lost (e.g. removed trees)