The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences. Vol. XXXVII. Part B5. Beijing 2008 
996 
The speed of data acquisition by terrestrial laser scanning with 
the mobile mapping system of VISIMIND could be increased 
significantly. 33 blocks could be scanned in 33 working days 
until the end of August 2007. Usually, scanning could be 
carried out five days per week (Mo-Fr, plus Sunday) starting at 
6.30 am until 2 pm of each working day. Consequently, the 
laser scanning of the remaining 50 blocks could be finished 
with the mobile system by November, 8 lh , 2007 with the 
improved total production rate of ~600m per hour, while post 
processing of the multiple sensor data took until January 2008. 
The production rate was mainly 1:10, i.e. for one hour scanning 
10 hours post processing was needed. In total, 12 operators of 
the laser scanning group were supporting the data post 
processing of the mobile mapping system during the major 
processing phase. Nevertheless, approximately 2% of the area 
(30ha) could not be scanned by mobile terrestrial laser scanning 
(TLS) due to traffic restrictions and environmental conditions. 
This remaining 2% of the total area must be scanned by static 
TLS at the end of the project in order to complete the data 
acquisition. At least two months will be needed for scanning by 
static TLS using all available laser scanning systems. 
4.3 Digital photogrammetry 
For photogrammetric documentation of the building facades as 
mentioned before, pre-calibrated SLR cameras Nikon D70 with 
14mm and 28mm lenses were used. The acquired images were 
processed in combination with the static terrestrial laser 
scanning data. When the mobile system was used for data 
acquisition, only the images of the integrated oblique and 
horizontal cameras (Figure 8) were used for mapping. The 
upper sideward looking camera is vertically rotated against the 
lower camera by approximately 34°, enlarging the vertical field 
of view of the camera system to approximately 86°, so that the 
camera system starts at an angle looking down to the street. 
Figure 8. Oblique and horizontal camera integration in the 
mobile system (left), image taken by oblique camera (right) 
5. MAPPING OF FACADES 
The geo-referenced point clouds from the laser scanning group 
were used for line mapping of the facades in a plot scale 1:200. 
The point clouds were segmented by two people using Cyclone 
software before mapping (Figure 9) to eliminate unnecessary 
points and to reduce the data volume to the requested minimal 
portions for the mapping software. 
In this project generation of façade maps with 1:200 plot scale 
is required. This extreme demand corresponds to a standard 
deviation of the positions with 0.2mm in the map and 4cm in 
the object space, but this extreme accuracy is required only as 
relative accuracy; for the absolute accuracy a standard deviation 
of 0.5mm in the map, corresponding to 10cm in object space 
should be sufficient. As a tolerance limit three times the 
standard deviation has been accepted. Therefore, the control 
point configuration and accuracy must always be checked to 
obtain this accuracy. While all problems of static and mobile 
scanning were solved, the delay in the control point 
determination was a bottleneck in the production. 
Figure 9. Segmentation of a point cloud 
The facade mapping group consists of 34 operators using 34 
licences of the Menci-software Z-MAP Laser from Italy, which 
is able to process laser scan data and rectified photogrammetric 
images simultaneously for line mapping with limited AutoCAD 
functionality. It was estimated that approximately 5 million m 2 
of facades have to be mapped. The production rate was similar 
to the static laser scanning group: 80 ha with 32 operators in 
approximately 6 months. With regards the facade area, in total 
81,000 m 2 could be finished in 39 days, which corresponds to 
65 m 2 per person per day. The production rate could be 
increased from 60 m : of facade/day/operator (March 2007) on 
average to 140 m 2 /day (October 2007), which is more than a 
factor of a 2 time increase. If one assumes in total 5 million m 2 
façade area for mapping of the Historic Peninsula, it 
corresponds to an estimated mapping time of approximately 
five years with 34 operators working on 210 days per year. This 
estimation indicated that the mapping could not be finished 
before the deadline of the project. 
For data processing in Z-MAP all related data of the segmented 
part (point cloud, Nikon image(s), camera calibration file) was 
saved in one directory using the name of the block plus a suffix, 
e.g. 900 01. This block name is defined in the cadastre map. 
The HP workstations xw8200 used are equipped with dual 
XEON Processors (3.6 GHZ), 4 GB RAM and nvidea Graphic 
Cards with 256 MB RAM. For facade mapping the point cloud 
and one oriented image of the façade were used. Thus, the 
orientation of the photogrammetric image (usually recorded 
with the 14 mm lens) had to be determined by resection in 
space using at least five well distributed corresponding points 
(usually comers of windows) in the point cloud and in the 
image. For the adjustment of the spatial resection the calibration 
data of the pre-calibrated NIKON D70s are used. Usually the 
residuals of the control points were in the range of some 
millimetres, which indicated that sufficient results have been 
achieved. To carry out mapping with Z-MAP the images had to