Page 39 - Fister jr., Iztok, and Andrej Brodnik (eds.). StuCoSReC. Proceedings of the 2018 5th Student Computer Science Research Conference. Koper: University of Primorska Press, 2018
P. 39
l-time visualization of 3D digital Earth
Aljaž Jeromel
Faculty of Electrical Engineering and Computer
Science, University of Maribor
Koroška cesta 46, 2000 Maribor, Slovenia
aljaz.jeromel@student.um.si
ABSTRACT understanding of the planet [2].
A new method for real-time visualization of Earth in 3D is Quite a few methods for visualization of Earth and plan-
presented. The method dynamically calculates visualization ets have been developed and optimized since the historical
data and works in several steps. Firstly, the vertex coordi- Gore speech. During the years 2003 to 2006, a group of
nates in 3D are calculated. Then, the UV coordinates for Italian computer scientists presented a method for high per-
texturing are calculated from vertex’ position. The vertices formance terrain visualization, named BDAM, and two of
are connected into triangles and sent to the shader pipeline, its improvements, PBDAM and CBDAM [3, 4, 5]. Schnei-
where they are processed by vertex shader, geometry shader der and Westermann have also proposed a method using
and fragment shader. The vertex shader transforms the ver- nested meshes for high quality terrain rendering with min-
tices from the world space to screen space. Geometry shader imal GPU overhead in 2006 [6]. In 2007, Schafhitzel et al.
corrects possible interpolation errors by inserting extra ver- proposed a method for rendering of the planets, including a
tices where needed, while the fragment shader assigns the simulation of the atmosphere, in real-time [7]. A short book
colour to resulting fragments. The main advantage of the on planet visualization was written in 2008 by O¨ stergaard,
proposed method over the state of the art methods is its sim- which discusses the implementation challenges of a digital
plicity. Experimental results have shown that the proposed globe and presents the implementation solution with some
method produces a high FPS (frames per second), which optimizations [8]. Cozzi and Ring took that achievement one
makes it suitable for real-time visualization. step further in 2011, by writing an exhaustive book on vir-
tual globe design, along with multiple propositions on how
Keywords to deal with implementation issues that can occur, and the
full C# implementation [9].
Computer Graphics, 3D Rendering, Object Geometry
This paper is focused on real-time rendering of 3D Earth
1. INTRODUCTION map. A method for a dynamic visualization is presented
and explained, and the efficiency of the method is discussed.
With the use of 3-dimensional (3D) graphics, a lot of things The proposed method firstly calculates visualization vertices
can be visualized, from simple cubes to complex models of on the screen, then calculates their UV coordinates. The
real-life objects. The need for an application that visualizes results of these steps fill the Vertex Buffer Object, which
geographical and other data about the Earth in 3D has been is sent to the graphics card. There, the calculated vertices
expressed as early as 1998 by then vice president of the US are processed by the vertex shader, geometry shader, and
Al Gore [1]. He proposed many practical uses for such an the fragment shader programs, before the map is drawn on
application, named ”Digital Earth”. The proposed uses in- the screen. According to experimental results, the proposed
clude education, national border negotiations, redeployment method produces high enough FPS (frames per second) to
of police force to the most problematic areas, biodiversity be used in high performance applications. The proposed
preservation, climate change prediction and improvement of method is much simpler and light-weight than the state of
agricultural productivity. Because most world maps use the the art visualization methods. The floating point precision
Mercator projection, which deforms the view of the world, errors are handled by means of normalizing the coordinates
the visualization of Earth in 3D can teach the children a lot to the visible part of the Earth, while the interpolation errors
more about our planet than the conventional 2D maps can. are processed by the geometry shader on the GPU. This
The digital model of Earth, combined with many kinds of paper also does not concern itself with acquisition of texture
data (e.g. historical, geodetic, etc.) could also lead to better data; the implementation behind it is out of scope of this
paper.
This paper is organized as follows. The method for visual-
ization is explained in Section 2. The results, produced by
the method, namely frames per second (FPS) in relation to
the number of triangles rendered, are presented in Section
3. The conclusion is given in Section 4.
StuCoSReC Proceedings of the 2018 5th Student Computer Science Research Conference DOI: https://doi.org/10.26493/978-961-7055-26-9.39-42 39
Ljubljana, Slovenia, 9 October
Aljaž Jeromel
Faculty of Electrical Engineering and Computer
Science, University of Maribor
Koroška cesta 46, 2000 Maribor, Slovenia
aljaz.jeromel@student.um.si
ABSTRACT understanding of the planet [2].
A new method for real-time visualization of Earth in 3D is Quite a few methods for visualization of Earth and plan-
presented. The method dynamically calculates visualization ets have been developed and optimized since the historical
data and works in several steps. Firstly, the vertex coordi- Gore speech. During the years 2003 to 2006, a group of
nates in 3D are calculated. Then, the UV coordinates for Italian computer scientists presented a method for high per-
texturing are calculated from vertex’ position. The vertices formance terrain visualization, named BDAM, and two of
are connected into triangles and sent to the shader pipeline, its improvements, PBDAM and CBDAM [3, 4, 5]. Schnei-
where they are processed by vertex shader, geometry shader der and Westermann have also proposed a method using
and fragment shader. The vertex shader transforms the ver- nested meshes for high quality terrain rendering with min-
tices from the world space to screen space. Geometry shader imal GPU overhead in 2006 [6]. In 2007, Schafhitzel et al.
corrects possible interpolation errors by inserting extra ver- proposed a method for rendering of the planets, including a
tices where needed, while the fragment shader assigns the simulation of the atmosphere, in real-time [7]. A short book
colour to resulting fragments. The main advantage of the on planet visualization was written in 2008 by O¨ stergaard,
proposed method over the state of the art methods is its sim- which discusses the implementation challenges of a digital
plicity. Experimental results have shown that the proposed globe and presents the implementation solution with some
method produces a high FPS (frames per second), which optimizations [8]. Cozzi and Ring took that achievement one
makes it suitable for real-time visualization. step further in 2011, by writing an exhaustive book on vir-
tual globe design, along with multiple propositions on how
Keywords to deal with implementation issues that can occur, and the
full C# implementation [9].
Computer Graphics, 3D Rendering, Object Geometry
This paper is focused on real-time rendering of 3D Earth
1. INTRODUCTION map. A method for a dynamic visualization is presented
and explained, and the efficiency of the method is discussed.
With the use of 3-dimensional (3D) graphics, a lot of things The proposed method firstly calculates visualization vertices
can be visualized, from simple cubes to complex models of on the screen, then calculates their UV coordinates. The
real-life objects. The need for an application that visualizes results of these steps fill the Vertex Buffer Object, which
geographical and other data about the Earth in 3D has been is sent to the graphics card. There, the calculated vertices
expressed as early as 1998 by then vice president of the US are processed by the vertex shader, geometry shader, and
Al Gore [1]. He proposed many practical uses for such an the fragment shader programs, before the map is drawn on
application, named ”Digital Earth”. The proposed uses in- the screen. According to experimental results, the proposed
clude education, national border negotiations, redeployment method produces high enough FPS (frames per second) to
of police force to the most problematic areas, biodiversity be used in high performance applications. The proposed
preservation, climate change prediction and improvement of method is much simpler and light-weight than the state of
agricultural productivity. Because most world maps use the the art visualization methods. The floating point precision
Mercator projection, which deforms the view of the world, errors are handled by means of normalizing the coordinates
the visualization of Earth in 3D can teach the children a lot to the visible part of the Earth, while the interpolation errors
more about our planet than the conventional 2D maps can. are processed by the geometry shader on the GPU. This
The digital model of Earth, combined with many kinds of paper also does not concern itself with acquisition of texture
data (e.g. historical, geodetic, etc.) could also lead to better data; the implementation behind it is out of scope of this
paper.
This paper is organized as follows. The method for visual-
ization is explained in Section 2. The results, produced by
the method, namely frames per second (FPS) in relation to
the number of triangles rendered, are presented in Section
3. The conclusion is given in Section 4.
StuCoSReC Proceedings of the 2018 5th Student Computer Science Research Conference DOI: https://doi.org/10.26493/978-961-7055-26-9.39-42 39
Ljubljana, Slovenia, 9 October
