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ISPRS, Vol.34, Part 2W2, “Dynamic and Multi-Dimensional GIS”, Bangkok, May 23-25, 2001 
File Edit Marking Referencing Project Display Window . Help 
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immediately obtained: 74cm. This could be a very convenient 
and attractive function for many users. The firemen for example, 
would appreciate this approach for obtaining the sizes of some 
doors and windows immediately in case of fire. This is much 
Fig. 3. Direct measurement of a window width on the digital photograph (source: Deng, [1999, p.61]). 
more user-friendly and reliable compared with the practice of 
identifying the right lines and figures in the complex engineering 
drawings, especially for the people who are not familiar with the 
engineering drawings. The accuracy of the distance, when 
dealing with the non-metric digital camera image and no 
pre-calibrations for the camera, could be up to 1/1,700 in object 
space according to the test made by the author (Deng, 2001) by 
using PM Pro. Better accuracy was reportedly achieved by 
pre-calibration of the cameras with the Camera Calibrator 
provided by PM Pro (Hanke, 1998). Even higher accuracy could 
be expected when metric cameras were used. It remained as a 
problem however when scanned hard copy images were used 
and the modeling of the scanning errors, including the 
dominating geometric errors and sometimes the less dominating 
radiometric errors, were not properly handled (Shortis and Beyer, 
1996), it brought about obvious influences on the accuracy. 
3. 3D Model Construction and Direct 3D Measurement: 
Different forms of output are available from PM Pro, including 
table text formats of the analytical results of 3D coordinates and 
camera parameters, ortho photos of selected planes and 
adjusted 3D models with or without photo texture for 3D viewing, 
CAD or animation. The frame of the 3D model is constructed by 
the adjusted 3D points marked for processing or measurement 
in advance. The model can be optionally formed by points, lines, 
surfaces and photo texture surface covered model with or 
without point and line marks. The formats of the PM Pro output 
are compatible to most of the related current data formats, 
including text formats, image formats and CAD formats. Once 
the 3D model is constructed by PM Pro, it can be used for both 
3D viewing and direct 3D measurement. For 3D viewing, a 3D 
model produced by PM Pro can be viewed from different angles 
by rotating the model on computer screen with the mouse, the 
model can also be magnified or minified on the screen. As a 
good example of the application of the 3D model created by PM 
Pro, an impressive virtual reality modeling project can be found 
in a EOS project on the web (EOS, 2001). The viewer “walks” in 
this project through a downtown street formed by a VRML model 
created with PM Pro. 74 photographs and over 1000 3D points 
were used in PM Pro for the modeling. The animation effect and 
the photo texture covering over the model makes a good real life 
result. For the direct 3D measurement, the 3D point coordinates, 
distances and areas can be measured directly on or between the 
point marks on the 3D mode under the measure mode. 
4. Engineering Drawing Production: The engineering 
drawings of an object can be obtained by loading the 3D result 
of PM Pro into CAD after PM Pro has finished processing the