International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part B-YF. Istanbul 2004
Figure 8. Bird View of 3-D Photorealistic Model for Purdue Campus .
5. CONCLUDING REMARKS
This study has successfully integrated photorealistic
visualization capabilities into a 3-D GIS. Some useful
experience is gained through this process. First, a 3-D
geospatial geometric model needs to be carefully selected
based on the multiple considerations, such as the definition of
3-D geometry and topology, support of geospatial query, and
effective texture mapping. It is shown that PolygonZ structure
is an appropriate choice that can accommodate all the
considerations with certain amount development and
enhancement. Next, texture mapping is a crucial step in
photorealistic visualization. In our study, a model based ortho
rectification is developed to produce true ortho image based on
building models. In this way, all building roofs can be easily
mapped to the texture to achieve an effective 3-D rendering.
Third, we successfully achieved an automatic association of
building walls to their corresponding textures. This
significantly reduces the amount of time for texture mapping,
which is usually carried out manually.
Future efforts will be made to improve our work. Other
possibilities in effective 3-D data model will be explored to
further simplify the texture mapping and rendering operations.
Another problem is the consistency between roof texture and
vertical wall texture in terms of color, resolution, contrast and
spatial accuracy. In addition, we will make development to
include more complex geospatial features and other geospatial
information.
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