Parameters of selected groundbased observing stations.
n int number specifying observing station Either given or returned *c char identifier specifying observing station
*name char name of specified observing station *w double longitude (radians, West +ve) *p double geodetic latitude (radians, North +ve) *h double height above sea level (metres)
Station identifiers may be up to 10 characters long, and station names may be up to 40 characters long. Leading or trailing spaces are not supported. c and n are alternative ways of specifying the observing station. The c option, which is the most generally useful, may be selected by specifying an n value of zero or less. If n is 1 or more, the parameters of the nth station in the currently supported list are interrogated (n=1 meaning the first station in the list), and the station identifier c is returned as well as name, w, p and h. If the station parameters are not available, either because the station identifier c is not recognised, or because an n value greater than the number of stations supported is given, a name of "?" is returned and c, w, p and h are left in their current states. Programs can obtain a list of all currently supported stations by calling the routine repeatedly, with n=1,2,3... When name="?" is seen, the list of stations has been exhausted. Station numbers, identifiers, names and other details are subject to change and should not be hardwired into application programs. All station identifiers c are uppercase only; lowercase characters must be converted to uppercase by the calling program. The station names returned may contain both upper- and lowercase. All characters up to the first space are checked; thus an abbreviated ID will return the parameters for the first station in the list which matches the abbreviation supplied, and no station in the list will ever contain embedded spaces. c must not have leading spaces. IMPORTANT -- BEWARE OF THE LONGITUDE SIGN CONVENTION. The longitude returned by slaObs is west-positive in accordance with astronomical usage. However, this sign convention is left-handed and is the opposite of the one used by geographers; elsewhere in slalib the preferable east-positive convention is used. In particular, note that for use in slaAop, slaAoppa and slaOap the sign of the longitude must be reversed. Users are urged to inform the author of any improvements
typographical corrections more accurate parameters better station identifiers or names additional stations Defined in slamac.h: DAS2R P.T.Wallace Starlink 17 November 1993