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SYMBOLICAL 3D VISUALIZATION OF GENERALIZED CARTOGRAPHIC
DATABASE AT A SCALE 1: 25,000
Lojze Miklavéié, B.Sc.Geod. ** , Duian Petrovié, Ph.D.Geod.^
"Geodetic Institute of Slovenia, Jamova 2, 1000 Ljubljana, Slovenia - lojze.miklavcic@geod-is.si
? Faculty of civil engineering and geodesy, Jamova 2, 1000 Ljubljana, Slovenia - dusan.petrovic@geod-is.si
KEY WORDS: Generalized cartographic database, DEM, 3D symbolization, Visualization
ABSTRACT:
Nowadays demands for 3D visualizing in land development, tourism, and cartography are increasing and therefore it is necessary to
provide fast and adaptable visualizations. To be able to provide such needs, we have to develop methods for 3D visualization of
existing spatial databases.
In early 90's Mapping and Surveying Authority of Republic of Slovenia (SMA) started the project of vectorizing national
topographic map at a scale 1: 25,000. In next years a generalized cartographic database at scale 1: 25,000 (GKB 25) arises and it
contains several cartographic features:
- communication network (motorways, roads, paths, railways etc.),
= hydrologic network (sea, lakes, rivers, sources, waterfalls, ete),
- relief contours (equidistance of 10 m).
These datasets are suitable for 3D presentation of larger areas and also for generating 3D maps and provide numberless possibilities
using methods of 3D visualization. We just have to decide how to present available data in 3D space in such manner that they can be
fast and easy readable. One of the most using ways to accomplish this task is photo-realistic visualization. Unfortunately, photo-
realistic visualization can't provide such amount of information as symbolic presentation. Instead of using methods of photo-realistic
visualization, we decided to use methods of symbolic visualization, visualization methods that are closer to the contemporary
cartographic methods.
1. INTRODUCTION 2. GENERALIZED CARTOGRAPHIC DATABASE AT
SCALE 1 : 25,000
A computer technology development and a wide range of
computer tools. have brought many changes In practical — Generalized cartographic database at scale 1: 25,000 (GKB25)
cartography. Visualization techniques and possibilities for contains vectorized data which were acquired by semi-
communication between user and computers sivc an — nutomatic vectorization. frem. scanned reproduction sheets of
opportunity to design new landscape representations. They topographic map at scale 1: 25,000. National topographic map
would enable users better terrain interpretation resulted in more of Slovenia consists of 200 non-overlapping sheets. Same sheet
efficient and complete spatial data capturing corresponding to classification is used in a generalized cartographic database and
the traditional two-dimensional paper or screen maps. each sheet of GKB25 contains described data layers:
- communication network (linear topology)
- railways (point, linear and area topology)
- hydrologic network (point, linear and area topology)
- relief contours (linear topology)
Each data layer is saved as a separate ARCINFO cover
depending by topology type with corresponding attribute data.
Attribute data contain attributes extracted from the scanned map
and some attributes extracted from other existing databases. In
example below an attribute table of linear object in the
hydrologic network is shown.
One of those possibilities is producing three-dimensional
cartographic model (3D map) as a new approach in landscape
presentation. The main benefit of 3D maps regarding 2D maps
is more realistic and user-friendlier height presentation. Besides
this 3D maps offers many new possibilities of use: simulations
of moving in real time, simulations of placing new objects on
landscape, dynamic phenomena analyses, etc. Users can observe
3D map on computer screen, where proper software offers him
to choose a viewpoint and a distance. But it is also possible to
print selected view on a paper sheet and use it as a traditional
perspective or ordinary 2D map.
name type description
For complete landscape presentation besides data from GKB 25 |Dat_vzd date Date of last change
we took also some other data from other databases under SMA Dat zaj date — Date of vectorization
competence. In a proposed paper it will be described, how all of Id hmz integer (ID in hydro-meteorological register
the relevant data were prepared, what were the main procedures
: en Id povod | integer ID of adequate watershed
and finally, some of the most interesting and significant results
St vod integer |Identification number
Will be presented. : :
Tip vod integer |Type of hydrological object
Virl integer |Source for vectorization
Table I. Attributes of linear object in hydrologic network
* Corresponding author
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