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International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Volume XXXIX-B4, 2012 
XXII ISPRS Congress, 25 August — 01 September 2012, Melbourne, Australia 
Since every pixels of a true 3D image have their own 
XYZ coordinates, reading positions/locations, 
measuring distances, horizontal areas and vertical 
areas (such as a window), volumes, profiles, etc. 
become straight forward processes. 
2.2.3 Making 3D Models 
True 3D images can be used to produce 3D models, 
such as 3D city models. 3D city models made by such 
true 3D images look realistic, accurate, complete, and 
consistent and very importantly they are measurable, 
not just for look. Making 3D city models with true 3D 
images is a unique approach and there are several 
advantages associated with this approach. First, this 
approach bypasses the time consuming and labor 
intensive cut-and-paste processes that most people use 
today to make 3D building models. This approach 
saves a lot of time and labor work. Second, the 3D city 
model made by this approach look realistic, complete, 
and consistent comparing with the fake looking, 
incomplete, and inconsistent 3D city model by today’s 
common practices. Third, the 3D city models made by 
this approach are measurable comparing with many 3D 
city models that are only for look. Figure 3 and 4 are 
examples of 3D city model made by this approach for 
Orlando, Florida. 
2.2.4 Other Potential Applications 
Because of the realistic and measurable characteristics 
of the 3D city models or just 3D models produced by 
the true 3D images, basically the 3D models can used 
at any places where accurate, realistic, consistent, and 
complete 3D information is needed. For examples, 
they can used for: 
Public safety and security 
City planning and construction 
Telecommunications 
Military exercise simulations 
Pilot training simulations 
Environmental protection and monitoring 
Surveying and mapping 
Others 
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: Figure 2^ perspective view of 3D Orlando 
  
Figure 4. Another perspective view of 3D Orlando. 
3. FINAL REMARKS 
Comparing with today's widely used 2D 
orthophotos, true 3D images can provide an 
additional third dimension Z to users while 
preserving all the features of 2D orthophotos, 
therefore true 3D images should become a 
standard layer in any Geographic Information 
System in the future. 
The era of realistic and measurable 3D models is 
coming. During the last several years, people 
started to try to produce realistic 3D city models. 
In this effort, 3D models produced by using the 
true 3D images are playing a leading role. The 3D 
models produced by using the true 3D images 
represent the ultimate standard of a 3D model. 
The ultimate standard for a 3D model is that such 
a 3D model should present all the objects in the 
scene it covers realistically, accurately, 
completely, consistently, and measurable.