Table 2 Properties of measurement data. Asterisk (*) indicates that, only for this case, the UAS point cloud was registered to the UAS point cloud of number 3 (Feb. 11, 2015) because of the lack of TLS data
| Â | Number of surveys | 1 | 2 | 3 | 4 | 5 | 6 | 7 |
|---|---|---|---|---|---|---|---|---|
| Â | Data of measurement | Jun. 24, 2014 | Oct. 31, 2014 | Feb. 11, 2015 | Jun. 18, 2015 | Oct. 23, 2015 | Feb. 23, 2016 | Jun. 18, 2016 |
Weather | Cloudy | Cloudy | Sunny | Sunny | Sunny | Sunny | sunny | |
Period length (days) | – | 129 | 103 | 126 | 120 | 131 | 116 | |
TLS | Number of TLS scan position | 1 | – | 10 | 6 | 4 | 6 | 8 |
Internal registration errors (mm) | – | – | 5.3 | 3.5 | 8.9 | 15.9 | 11.7 | |
Total number of TLS points measured | 750,045 | – | 138,546,188 | 67,488,458 | 36,013,373 | 56,232,226 | 65,453,912 | |
Number of TLS points used | 294,888 | – | 990,882 | 14,062,296 | 2,624,403 | 4,508,131 | 5,895,657 | |
GNSS | Number of GCPs | 4 | – | 7 | 6 | 3 | 6 | 5 |
Horizontal errors in GCP (mm) | 16.8 | – | 14.9 | 13.5 | 14.3 | 13.4 | 13.6 | |
Vertical errors in GCP (mm) | 21.8 | – | 29.4 | 29.2 | 21.3 | 24.6 | 22.8 | |
ICP | External registration errors (mm) | 13.9 | – | 21.2 | 8.1 | 6.4 | [BASE] | 10.6 |
UAV | UAS registration errors (mm) | 33.5 | 18.8* | 39.7 | 24.6 | 30.1 | 25.1 | 30.2 |
Total number of measured points used | 18,319,013 | 10,926,651 | 63,738,045 | 46,470,682 | 18,468,025 | 24,070,025 | 16,751,012 | |
Number of points used | 9,761,070 | 5,172,098 | 34,949,713 | 25,753,386 | 7,181,782 | 7,032,236 | 7,042,244 |