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Preface [] is an exposition website for early previews of digital works related to interactive 3D Earth models. Here demonstrates some implementation samples of technology around an earth, such as efficient outer-spherical mapping and advanced user interactivity with spherical 3D models, which are applicable to visual interfaces of geographic infomation systems(GIS). Please get in touch with the a piece of technology and imagine a lot about future of geo-conscious information systems.

*Application samples exhibited on this website are built on Flash®/ActionScript™ so that these can be deployed easily through the internet. But the core technologies used in the samples are primarily platform independent. Therefore, these are also utilizable for other platforms or technologies, such as OpenGL®, DirectX®(managed/unmanaged), XNA®, Windows® Presentation Foundation (WPF/XBAP), Silverlight®, Java™, JavaFX™ etc.

*Flash and ActionScript are either registered trademarks or trademarks of Adobe Systems Incorporated. OpenGL is a registered trademark of SGI. Windows, DirectX, XNA, and Silverlight are registered trademarks of Microsoft Corporation. Java and JavaFX are trademarks of Sun Microsystems Inc.

Spherical Model in 3D Graphics

A sphere is one of the most fundamental shapes in the universe. However drawing a sphere on computer screen is one of the most advanced topics of 3D graphics. Because a sphere (curved face with no edge) has the least affinity with standard 3D computer graphics nowadays that draws objects with polygons (flat face bounded by straight edges). Developers have to tackle a little bit deep theme, how to approximate such an infinitely curved model by minimal set of polygons to balance good quality (sphericalness) and good computational or otherwise rendering performance.

Sometimes, there seem to be 3D beginners beaten thoroughly by choosing drawing a sphere (or 3D Earth) as a first theme of development. If you are one of such unlucky developers, please remember that a basic 3D model suitable for learners' first step is not a sphere (but a cube). Drawing a spherical model might be the final theme left in your carrier.

Requirements for 3D Earth Development

Math skill level required to draw a sphere is a little bit higher than that for other conventional 3D models. Developers need to solve equations not only in common Cartesian 3D coordinate space(x,y,z) but also in polar coordinate space(r,theta,phi) in various aspects of development. And also, some skills or knowledge of physics(rigid-body kinematics) and cartography(map projections) are to be required, when developer turns a sphere to an immersibly operatable 3D Earth model.

Basics of matrix and vector algebra, Math to handle polar coordinates(sin, cos, tan) To compose or handle a sphere or its surface numerically in source code
+ Math to solve sinusoidal equations, Rigid-body kinematics.To design or program complicated animations or user interactions for spherical models
Academic-level mathematics.To fully tackle the problem of perfect polygon meshing onto spherical surface

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