Subroutine: IRCO_RECTOTWIST. Purpose: Transform from rectangular to spherical coordinates. Category WORLD COORDINATES, IRAS File: irco.shl Author: 900921 Do Kester Use: call IRCO_RECTOTWIST ( xyz I doubleprecision(3,n), twv I doubleprecision(3,n), lon O doubleprecision(n), lat O doubleprecision(n), twist O doubleprecision(n), n I integer. ) xyz rectangular coordinates of the direction twv rectangular coordinates of the twist angle lon (in radians:) longitudes lat (in radians:) latitudes, twist (in radians:) twist angles counterclock from north n number of vectors to be transformed. Description: This module does the opposite of IRCO_TWISTORECT. A vector of length zero will give a latitude and a longitude of 0.0. If x and y are zero then it is a pole and the longitude will be 0.0. Updates: 90 Apr 24 Sjag Steensma; documentation only.