The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences. Vol. XXXVII. Part B5. Beijing 2008 
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• Groups characterizing the morfometric structure of the 
terrain and they have a GLOBAL character, contained in the 
TERRAIN category. It contains the information of bench 
marks on the terrain, coast lines, reservoir lines, curved of 
level and pickets generated by published meshes. 
• Groups that conform closed lines with topologies 
differentiated in areal layers to develop the defined three- 
dimensional objects as POLYGONS and they have a 
LOCATED nature. Other elements described in the 
structures such as sidewalks, blocks, parcels and buildings 
are including and are described from its TOP view in the 
Photogrammetric Stations and they have a hierarchical order 
in accordance with the function of their location on the 
terrain, evaluating the space characteristics which precedes it. 
The defined color for the layer is assigned to the sidewalk 
elements as well as defined values to the buildings elements 
with defined values of texture defined by the user or they may 
be aleatory according to the selected palette of colors, allowing 
the differentiated visualization of each object, including the 
contiguous structures mediating in adjacent buildings. 
The routes are defined by the lines of parallel sidewalk 
conforming closed spatial shapes 
The hydrographic elements will be treated in their edges 
defining the line of maximum bench mark. In the case of the 
coast the line will be created by water line or the “bench mark 
zero” when it is not perceptible. This element in the modeling 
scene should have a closed conformation. 
4.1 Modeling the terrain 
The digital pattern of the land is created by implementing the 
algorithm of triangulation Delaunay, which generates 
equilateral triangles starting from the supplied data 3D. 
The determined points using the photogrammetric technical 
define the surface of the ground, CartoSIG manages the data in 
structure 2D keeping the value of the height in the " Elevation " 
field. 
The Delaunay algorithm has been applied under the variant of 
incremental triangulation [3], to eliminate redundant points on 
oneself position or erroneous, validating each one of the edges 
so that they fulfill the condition, being modified when the 
condition is not satisfied with in reference to the addition value 
of internal angles and its distribution, ccording to informatics 
terminology in computer terms this algorithm can diminish its 
temporary cost to O(nlogn) if logarithm cost data structures are 
used, the type of binary tree balanced of searching (AVL). 
4.2 Polygons Modeling 
A polygon is compound for a sequence of vertexes, ordered in 
counter-clockwise direction to guarantee a correct visualization 
of the object when establishing the normal vectors in the correct 
projection to assume the global effects of illumination, tone, 
texture and shadowing in the same sense. 
The modeling of the polygons can be implemented by diverse 
algorithms, according to the characteristics of the elements to be 
processed: 
4.2.1 Triangulation of monotonous polygons for holed 
polygons 
A simple polygon can always break down in monotonous pieces 
carrying out a sweeping of the plane (algorithm plane-sweep). 
Once divided each piece is triangulated by the algorithm of 
monotonous triangulation. 
4.2.2 Triangulation with Sweeping of points for the regular 
polygons 
The sweeping of the elements that conform the polygon allows 
their decomposition, and at the same time diagonals are added 
to go conforming the pieces of minimum structure (triangular) 
considered as monotonous. 
The lack of horizontal monotony only exists in the vertexes 
which interior angle is bigger than 180° and both edges are 
towards its left or its right. 
The basic elements of the algorithm are: 
• Stopping points: The ends of the segments of the polygon. 
• Sweeping state: It is given by the list of edges intersecting 
the sweeping line. 
• Processing of the stopping points: In the algorithm they are 
six types of stopping points, in dependence of the condition 
that fulfilled define aspects: .separation, union, beginning, 
ending, superior chain, inferior chain. 
Once the polygon was triangulated, the SIG only provides the 
superior part of the object which was created using stereo 
photogrammetric methods. It presupposes the projection to the 
preceding object or in it hierarchical order or in its defect until 
the terrain. The polygon vertexes are manipulated in counter 
clockwise, an calculating the perpendicular up to the terrain, an 
intersection point is created and the faces of the polygon will be 
drawn with the original and those projected vertexes. 
5. ACHIEVED RESULTS 
The Modulo3D application on the platform CartoSIG has been 
evaluated considering the information created by stereo 
photogrammetric method for mapping the plans to scale 1:500 
of an urban environment. The evaluated region is divided by a 
river that ends in the sea in the Havana Coast. In Figure 3 
different views of the system are represented with the modeling 
urban environment. 
6. TECHNICAL REQUIREMENTS 
The CartoSIG system with the module of integrated handling 
3D needs the following requirements to work in an efficient 
way with an acceptable speed: 
" 128 Mb of RAM as minimum, 
" lGhz of speed (Ideal PIV with 2 GHz), 
" Video card with more than 128 Mb. 
" Framework 2.0. 
7. CONCLUSIONS AND RECOMMENDATIONS. 
After validating the structure of the application of Modulo3D 
and its integration to platform CartoSIG the objective of 
developing a tool inserted in a platform SIG that allows the 
interaction, handling and visualization of the environment and 
the objects that integrate it in a general and detailed mode, and 
representing them in their correct geographical location, 
magnitudes and geometry.