Pablo, You need to be more explicit with respect to what you have and what you want to do with what you have. For instance, the GPS satellites broadcast their positions in the geocentric coordinate system with respect to the WGS84 Datum (XYZ). GPS receivers commonly output readouts in Latitude, Longitude, Ellipsoid Height or sometimes UTM (X,Y, Ellipsoid Height). Some "shirt-pocket" grade receivers (Garmin 12XL) can also provide a "local" user-defined Transverse Mercator Grid that is (X,Y, Ellipsoid Height.) Some receivers are differential-capable and can provide better accuracy than single point-positions on a single-frequency 8-12 channel receiver 5 meters versus 15 meters to 100 meters accuracy), some are dual-frequency and in differential mode can provide relative positions better than one centimeter horizontal, two centimeters vertical with appropriate observational techniques and post-processing. You have "X's and Y's coordinates that you obtained with GPS in WGS84 Datum." That's not good enough a description. "How do I translate that to another in Venezuela???" Well, Pablo, there are a number of coordinate systems that exist in Venezuela. There's the Loma Quintana Datum of 1911 that has X,Y coordinates on the Compensated Secant Conic Projection, and the Provisional South American Datum of 1956 (origin a La Canoa) that has X,Y coordinates on the UTM Grid. Both Datums use the International Ellipsoid of 1909. Furthermore, there are over three dozen (36+) local Grids used on the Loma Quintana Datum of 1911 that were developed by various oil companies in the 1920's through the 1950's. Some of these also include the Maracaibo Systems (in the plural), on the Loma Quintana Datum of 1911: Lake Maracaibo Lambert I, Lake Maracaibo Lambert II, Puerto La Cruz Polyhedric, Pirit� Polyhedric, Maracaibo Vicinity Oil Grids (many), Barcelona Vicinity Oil Grids (many), Matur�n Vicinity Oil Grids (many), and many Dabajuro Vicinity Oil Grids. Other Datums in Venezuela include: Bah�a Honda Datum, Castiletes Datum, Estanques Datum, Soldano Rock Datum,Testigos Astro Datum, Zapara Island Datum, Old Trinidad Datum of 1910 & Naparima Datum 1972 (the latter two transferred from Trinidad since the 1940's and obviously later). Furthermore,on the PSAD 1956 there is also the La Canoa Polyhedric, and on the Old Trinidad Datum of 1903, the Trinidad Cassini-Soldner and the Tobago Cassini-Soldner exist in the far east (Pedernales). Pablo, I've been to la Cartografia Nacional, I've lectured in Geodetic Software to their staff, and I've just scratched the surface of the complexity of the Venezuelan Coordinate Systems. I have even met with Dr. Romero (in 1984) and I interviewed him on his personal efforts in establishing the Datum Origin at La Canoa. That old gentleman was rightfully proud of his superb design and execution of one of the last well-done classical geodetic datums in the world. So, Pablo, you say you want to go to a local Grid in Venezuela. Pray tell, which one? Cliff Clifford J. Mugnier ([EMAIL PROTECTED]) The Topographic Engineering Laboratory Department of Civil and Environmental Engineering UNIVERSITY OF NEW ORLEANS New Orleans, Louisiana 70148 Voice and Facsimilie: (504) 280-7095 -------------------------------------------------------- -------------------------- On Tuesday, 08 June, 1999 9:08 AM, Catherine Galgano [SMTP:[EMAIL PROTECTED]] wrote: > > Can anyone help Pablo? > > ---------- > From: Unregistered <[EMAIL PROTECTED]> > To: '[EMAIL PROTECTED]' > Subject: INFORMATION > Date: Tuesday, May 04, 1999 8:39 AM > > HI, My name is Pablo I�m from Venezuela I need some > information, if I have > X�s and Y�s coordinates that i obtain with GPS and it have > the datum WGS84 > how I can change or how I can traslate that coordinates > whit that datum to > another in Venezuela??? in MAPINFO??? > thank you > ---------- > > ---------------------------------------------------------- > ------------ > To unsubscribe from this list, send e-mail to > [EMAIL PROTECTED] and put > "unsubscribe MAPINFO-L" in the message body, or contact > [EMAIL PROTECTED] ---------------------------------------------------------------------- To unsubscribe from this list, send e-mail to [EMAIL PROTECTED] and put "unsubscribe MAPINFO-L" in the message body, or contact [EMAIL PROTECTED]
