The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences. Vol. XXXVII. Part B4. Beijing 2008 
Figure 5. GML3 Editor (Plug in for Autocad®) 
With this software you can browse the dataset previously 
exported, querying it to know attributes of objects, as well as 
their hierarchical composition. 
This browsing module, that allows opening and browsing the 
model in GML3 format, has been built using open source 
libraries, like IRRLICTH (graphical engine) and WX widget 
(display framework), and MingW as compiler. 
The Irrlicht Engine is an open source high performance realtime 
3D engine written and usable in C++. It is completely cross 
platform (Windows, Linux, Mac), using D3D, OpenGL and its 
own software Tenderer, and has powerful features for 3D 
rendering. It supports many kinds of illuminations and shade's 
representations; its mathematic matrix subsystem can make 
high speed matrix computations. 
Software allows you to optimize lines' visualization (Figure 6), 
using each line just once; this is due to the structure of the file, 
written in GML3 format by the modeler inside Autocad®, with 
points and edges identified unequivocally. The lack of double 
lines simplifies a lot the rendering operations; besides it avoids 
the annoying visual effect due to overlapping lines. 
Main features of the software are: 
• loading of the cartographic structure with its attributes, 
using the GML3 format; 
• browsing of the model, with pan and zoom functions 
available both by mouse or by keyboard; 
• querying cartographic objects; 
• tree-visualization of each component of cartographic 
elements, with graphic highlighting of selected 
elements, and vice-versa; 
• solid or wireframe visualization mode; 
• dependently on the kind of element, the visualization 
color can be chosen from a palette; 
• the point of view can be modified by the user; 
At this stage of development, this browser cannot load texture 
for every object, but this feature is under further development. 
Figure 7. Visualization's options 
Browser allows the assignment of different colours to different 
surfaces, like walls or roofs of a building, so distinct elements 
cab be easily detected (Figure 7). 
This plugin is still under development, to improve the final-user 
interface and importing features. 
6.CONCLUSIONS 
Cartography needs are considerably growing day by day; so, 
starting off with this requirements and on the basis of studies 
carried out on existing cartographic models, a new cartographic 
model has been defined and called GIANT3D. Cartography 
structured according to this model is geometrically and 
topologically correctly structured, and it's suitable to be used in 
GIS. 
Main features of this model are: 
•structure according to indication of rules coming from OGC 
and ISO 19100 series; 
•topological constraints defined together with the geometry; 
•features structured using 0, 1, 2, 3 dimensional primitives, with 
the constraint that each higher primitive derives from the lower; 
•aggregate objects not defined; 
•edges composed by straight lines and planar faces;