SUBROUTINE sla_CC2S (V, A, B) *+ * - - - - - * C C 2 S * - - - - - * * Cartesian to spherical coordinates (single precision) * * Given: * V r(3) x,y,z vector * * Returned: * A,B r spherical coordinates in radians * * The spherical coordinates are longitude (+ve anticlockwise looking * from the +ve latitude pole) and latitude. The Cartesian coordinates * are right handed, with the x axis at zero longitude and latitude, and * the z axis at the +ve latitude pole. * * If V is null, zero A and B are returned. At either pole, zero A is * returned. * * Last revision: 22 July 2004 * * Copyright P.T.Wallace. All rights reserved. * * License: * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program (see SLA_CONDITIONS); if not, write to the * Free Software Foundation, Inc., 59 Temple Place, Suite 330, * Boston, MA 02111-1307 USA * *- IMPLICIT NONE REAL V(3),A,B REAL X,Y,Z,R X = V(1) Y = V(2) Z = V(3) R = SQRT(X*X+Y*Y) IF (R.EQ.0.0) THEN A = 0.0 ELSE A = ATAN2(Y,X) END IF IF (Z.EQ.0.0) THEN B = 0.0 ELSE B = ATAN2(Z,R) END IF END