Barber, Mills, Bryan 
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Figure 4: Example of intensity (top left), range (top right) 
and full colour data (bottom left) from the Reigl LMS-Z210. 
(Courtesy Riegl GmbH, 3D Laser Mapping Nottingham and 
English Heritage). 
The display of a point cloud is the most basic level of viewing scanner data and when viewed dynamically, rotated, panned and 
zoomed on a computer, point clouds are an excellent tool for simple interpretation. However, when displayed static it can be argued 
that they lose much of their value. Point data may also be displayed as an image making it familiar to users, but unless the data cloud 
is of a sufficient resolution the image may appear small or blocky. 
Traditional presentation of survey data includes line drawings, orthophotographs and, more recently, rectified photography. Figure 5 
shows a traditional line plot produced in a Zeiss P3 photogrammetric plotter working to an English Heritage Survey specification 
(Bryan and Blake, 2000). It is a typical product of architectural photogrammetry. Figure 5 also shows a scan of the same facade 
using a Cyrax 2400 scanner, with a point spacing of 25mm; it has been meshed and lit in an attempt to show features similar to those 
on the line plot. It is clear that the scanner data does not immediately show the same level of detail as the line drawing but the effort 
required to produce the scanner data is lower, consequently survey costs may be reduced. While the line drawing required 
photography to be taken followed by eight hours of plotting, the scanner data was captured in 15 minutes and meshed on site. 
However currently a stereo pair is an accepted archive in documentation projects and is only used for plotting when, or if, required. 
What is the archive product from laser scanning? 
Figure 5: Left, an example of a traditional photogrammetric line plot and right, a meshed point cloud collected by a Cyrax 2400 scanner