GISTutorial.NET

Tulisan dalam Bahasa Inggris berikut dari SQL Server Technical Article adalah salah satu tulisan yang sangat baik membahas tentang sistem koordinat. Writers: Isaac Kunen. Project Editor: Diana Steinmetz. Published: July 2008. Applies To: SQL Server 2008

Summary:

This paper is an introduction to Earth-oriented coordinate systems, projections, models, and mapping. While not specific to any technology, this information provides valuable background for those who will use spatial data in SQL Server.

Introduction: Teaching the Controversy

Contrary to popular opinion, Columbus did not prove that the Earth is round.[i] Pythagoras, Plato, and Aristotle claimed a round Earth based on philosophic and observational grounds. More impressively, Eratosthenes measured the Earth’s circumference around 240 B.C., a measurement which comes amazingly close to modern values—within 17 percent when taking pessimistic conversions into account and perhaps 2 percent if we’re more generous.

While there have always been—and likely will continue to be—people who steadfastly maintain that the Earth is flat, this is clearly an eccentric position. And yet, the most common representations of the Earth are flat maps. Thousands of years of effort have been put into flat representations of the Earth, and many of the techniques used are highly sophisticated and still quite valuable today.
The object of this short discussion is to explore this apparent contradiction and provide an introduction to both flat and round representations of the Earth, their uses, and their pitfalls, as well as to briefly discuss how modern developments continuously affect the way we work with the geospatial data. This is far from a comprehensive survey—entire books are devoted to these subjects—but we hope that this paper serves as a useful introduction to a surprisingly complex subject.

Read more… just visit the site

Source: http://msdn.microsoft.com/en-us/library/cc749633(v=sql.100).aspx