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3D VIRTUAL MODEL OF TURKEY 
A. Yilmaz, M. Erdogan, O. Eker 
General Command of Mapping, Photogrammetry Department, 06550 Dikimevi Ankara, Turkey 
(ayilmaz, merdogan, oeker)@hgk.mil.tr 
Commission IV, WG IV/6 
KEY WORDS: Photogrammetry, Remote Sensing, Orthorectification, DEM/DTM, Virtual Reality 
ABSTRACT: 
With the developments in computer technology, 3D models of objects are transferred to the digital form from the hardcopy form. 
Sometimes, the visualization of topography from the classical maps or orthophoto maps, which are enhanced with contour lines, 
can be difficult for users. So firstly, embossed maps have been used for topographic visualization. But the production of these 
kinds of maps is very difficult, very costly and time consuming. This visualization can be done digitally faster, cheaper and 
continuously. 
[n this Project, Landsat-7 images covering all Turkey are used. Firstly, panchromatic band and multi-spectral bands of the images 
were merged. For the best result, different merging algorithms were tested. In the second step, these images were ortho-rectified by 
using the ground control points and digital elevation models. The ortho-rectified images were mosaicked. 
3D visualization was performed by using Erdas Imagine Virtual GIS module. The model was enhanced with some additional data. 
Since the model covers a very huge area, gazetteer information was added to the model to show the location names. Also some 
boundaries and road network was superimposed to the visualization. The images of important and historical places were added. 
As a result of Project, a user can fly over all Turkey, may watch the topography, cities, historical and touristical places by using 
this model. Thanks to the computer technology, user can do this seamlessly with the preferred detail and scale. This technology is 
taking place of the classical embossed map with its inexpensiveness, flexibility and easy production. 
1. INTRODUCTION The project will help the pilots to fly over Turkey, instead of 
using 1:250.000 scale hardcopy maps in airplanes or 
With the developments in computer technology, 3D models of ^ helicopters. They can use it prior to the flight in flight planning 
objects are transferred to the digital form from the hardcopy process by 3D visualization. 
form. Sometimes, the visualization of topography from the 
classical maps or orthophoto maps, which are enhanced with It can also be used as a base in vehicles’ trip computer system 
contour lines, can be difficult for users. So firstly, embossed or in vehicle tracking system of a transportation company. 
maps have been used for topographic visualization. But the 
production of these kinds of maps is very difficult, very costly 
and time consuming. This visualization can be done digitally 2. THE PRODUCTION OF TURKEY MOSAIC 
faster, cheaper and continuously. 
2.1 Information About LANDSAT 7 
Geographic Information Systems (GIS) has developed rapidly 
in recent years. The need for a base in GIS arouse in small LANDSAT 7 was launched on April 15, 1999 from the 
scales, especially for a whole country. The representation of Western Test Range at Vandenburg Air Force Base on a Delta- 
information is as important as the information itself. It requires Il launch vehicle. At launch, the satellite weighed 
accuracy, completeness, exquisiteness. By using aerial approximately 4,800 pounds (2,200 kilograms). The spacecraft 
photography it was nearly impossible to produce orthophoto is about 14 feet long (4.3 meters) and 9 feet (2.8 meters) in 
mosaic of Turkey. Nearly 12500 aerial photos with a scale of diameter. It consists of a spacecraft bus, built by Lockheed 
1:35.000 were necessary to cover Turkey, let alone the time Martin Missiles and Space in Valley Forge, Pa., and the 
needed for photogrammetric and flight processes. Landsat 7 Enhanced Thematic Mapper Plus (ETM+) instrument, 
imagery was decided to be used. It has 15 meters resolution in developed by Raytheon Santa Barbara Remote Sensing in 
panchromatic mode and 30 meters in multispectral mode. Santa Barbara, Calif. 
These resolutions are enough for a nearly 1:1.000.000 scale à : : 
base. So it was suitable for a base map covering whole Turkey. The ETM+ instrument is an eight-band multispectral scanning 
Had the high resolution imagery (1-5meters) been used, the radiometer capable of providing high-resolution image 
volume and the cost of the mosaic would have been very great. information of the Earths surface. It detects spectrally-filtered 
radiation at visible, near-infrared, short-wave, and thermal 
infrared frequency bands from the sun-lit Earth. Nominal 
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