SPHLOS (Feb93)                    model                   SPHLOS (Feb93)



NAME
    sphlos
    
    
USAGE
    sphlos lsinim lsotim n1otim xcentr ycentr radius lati0 long0 semid
        jxinc jyinc mbytes
    
    
PARAMETERS
    
    lsinim
        List of input image names.
        The  input  is  assumed  to  be  a  scalar  or  vector  field in
        spherical coordinates.
        N3INIM:  3rd dimension of the input image.
        N3INIM is used as a processing option.
    
    lsotim
        List of output image names.
        N3OTIM:  3rd dimension of the output image.
        N3OTIM=N3INIM
    
    n1otim
        1st and 2nd dimensions of the output images.
    
    xcentr
        X coordinate of the disk center in pixels.
        1.0.LE.XCENTR.LE.FLOAT(N1OTIM)
    
    ycentr
        Y coordinate of the disk center in pixels.
        1.0.LE.YCENTR.LE.FLOAT(N2OTIM)
    
    radius
        Disk Radius in pixels.
        RADIUS.LE.FLOAT(N1OTIM/2)
    
    lati0
        Latitude  of the disk center in degrees.
    
    long0
        Longitude of the disk center in degrees.
    
    semid
        Semi-diameter of the disk in arc seconds.
    
    jxinc,jyinc
        Outer DO loop increments that can be used to control the  amount
        of  paging  when  processing  images that will not fit into real
        memory.  For 3-component, 1024**2 images on a 16MB machine
            JXINC=JYINC=150
    
    mbytes
        Available memory for image pixel arrays in Megabytes.
        This parameter can be used to  control  the  amount  of  virtual
        memory  paging  that  will  occur if all the pixel arrays do not
        fit into the available real memory.
    
    
IMAGE HEADER WORDS
    
    The three image dimension parameters are read from  the  header  for
    the input image:  LSINIM.
    
    The latitude type, LATTYPE, is read and checked to be 1.
    
    The  header  for the output image, LSOTIM, is copied from the header
    for the input image, LSINIM.
    
    The following output image dimension parameters are reset:
        IM_LEN(.,1) is determined from the input parameter, N1OTIM.
        IM_LEN(.,2) is determined from the input parameter, N1OTIM.
    
    The following parameters are written to the output image header:
    
        PIXLENX=1.0
        the x-direction size of the camera pixels
    
        PIXLENY=1.0
        the y-direction size of the camera pixels
    
        FNDLMBXC = XCENTR, an input parameter
        x coordinate of the center of the disk in pixels
    
        FNDLMBYC = YCENTR, an input parameter
        y coordinate of the center of the disk in pixels
    
        FNDLMBMI = RADIUS, an input parameter
        length of the semiminor axis in pixels
    
        FNDLMBMA = RADIUS, an input parameter
        length of the semimajor axis in pixels
    
        FNDLMBAN = 0.0
        angle between the semimajor axis and the y axis in degrees
    
        HELIOGB0 = LATI0, an input parameter
        Latitude  of the disk center in degrees
    
        HELIOGL0 = LONG0, an input parameter
        Longitude of the disk center in degrees
    
        HELIOGSD = SEMID, an input parameter
        Semi diameter of the disk in seconds
    
        HELIOGPA = 0.0
        Heliographic position angle.
    
    The task writes  processing  history  information  into  the  output
    header using 'gr_history' from 'grutil/'.
    
    
DESCRIPTION
    
    SPHLOS  performs  a line of sight correction to a field in spherical
    coordinates  on  the  solar  disk.   It  converts  the  field   from 
    heliocentric   spherical  coordinates  to  a  geocentric  observer's 
    rectangular coordinate system.  This task assumes square pixels.
    
    SPHLOS is from David H. Hathaway's modelling  code  for  "Simulating
    Photospheric Doppler Velocity Fields".
    
    N3, the 3rd dimension of the Input and Output Images, determines the
    processing option.
    
    If N3=1 
       I3=1 of the input image is assumed to contain the radial component.
       The radial component is transformed.
       The radial component is stored in I3=1 of the output image.
    
    If N3=2 
       I3=1 of the input image is assumed to contain the THETA component.
       I3=2 of the input image is assumed to contain the PHI   component.
       The THETA and PHI  components are transformed.
       The THETA component is stored in I3=1 of the output image.
       The PHI   component is stored in I3=2 of the output image.
    
    If N3=3 
       I3=1 of the input image is assumed to contain the radial component.
       I3=2 of the input image is assumed to contain the THETA component.
       I3=3 of the input image is assumed to contain the PHI   component.
       The radial component is transformed.
       The THETA and PHI  components are transformed.
       The radial component is stored in I3=1 of the output image.
       The THETA component is       stored in I3=2 of the output image.
       The PHI   component is       stored in I3=3 of the output image.
    
    
    
EXAMPLES
    
    
TIME REQUIREMENTS
    
    
BUGS
    
    
SEE ALSO
    sphspc
    sphinv