Zhijie: Coordinates are probably very important in not only analysis in R, but in all environments that deal with spatial data analysis as well.
Difference between the geographical coordinates (Lat. and Long.) and the planar coordinates (the x and y) is basically the difference between spherical coordinates and Descartes' two-dimensional Cartesian coordinates. Distance measurement will be different. In addition, geographical coordinates are always associated with specific Datum (NAD27, NAD83, WGS84, etc.), with different Datum, the same location can have different Lat. and Long. Planar coordinates, on the other hand, in spatial data analysis, are usually not only associated with specific Datum, but specific projection as well (UTM, SPCS, etc.) Coordinates are important in the field of Geology - I guess, but I would say coordinates are fundamental concepts from Cartography. Hence some good reference book in Cartography might provide further information on the question you ask. Hope this helps. Danlin Yu ___________________________________________ Danlin Yu, Ph.D. Assistant Professor Department of Earth & Environmental Studies Montclair State University Montclair, NJ, 07043 Tel: 973-655-4313 Fax: 973-655-4072 email: [EMAIL PROTECTED] ----- Original Message ----- From: zhijie zhang <[EMAIL PROTECTED]> Date: Wednesday, April 5, 2006 2:19 am Subject: [R-sig-Geo] confused by coordinates > Dear Friends, > Coordinate is common in geology/spatial science. There are > latitude/longitude coordinate, x/y coordinate,......... It maybe > easy for > all of you, but difficult for persons without the background > knowledge of > geology, so they can't do the correct analysis with different > coordinate,.In my opinion, it's very important to make clear on it > and its application > with R, can anybody with excellent knowledge obout it give some > guide on > using it with R? > For different coordinate, > A: > latitude longitude attribute > > B: > x y attribute > > -- > Kind Regards, > > [[alternative HTML version deleted]] > > _______________________________________________ > R-sig-Geo mailing list > [email protected] > https://stat.ethz.ch/mailman/listinfo/r-sig-geo > _______________________________________________ R-sig-Geo mailing list [email protected] https://stat.ethz.ch/mailman/listinfo/r-sig-geo
