;+ ; Project : STEREO ; ; Name : WCS_PROJ_LOG ; ; Purpose : Convert intermediate coordinates in LOG projection. ; ; Category : FITS, Coordinates, WCS ; ; Explanation : This routine is called from WCS_GET_COORD to apply the ; logarithmic (LOG) projection to intermediate relative ; coordinates. ; ; Syntax : WCS_PROJ_LOG, WCS, COORD, I_AXIS ; ; Examples : See WCS_GET_COORD ; ; Inputs : WCS = A World Coordinate System structure, from FITSHEAD2WCS. ; COORD = The intermediate coordinates, relative to the reference ; pixel (i.e. CRVAL hasn't been applied yet). ; I_AXIS= The axis to apply the projection to. ; ; Opt. Inputs : None. ; ; Outputs : The projected coordinates are returned in the COORD array. ; ; Opt. Outputs: None. ; ; Keywords : None. ; ; Calls : TAG_EXIST, NTRIM ; ; Common : None. ; ; Restrictions: Because this routine is intended to be called only from ; WCS_GET_COORD, no error checking is performed. ; ; Side effects: None. ; ; Prev. Hist. : None. ; ; History : Version 1, 06-Jun-2005, William Thompson, GSFC ; ; Contact : WTHOMPSON ;- ; pro wcs_proj_log, wcs, coord, i_axis on_error, 2 ; s0 = wcs.crval[i_axis] coord[wcs.i_axis,*] = s0*exp(coord[wcs.i_axis,*]/s0) ; end