NAME

       CPCLTR - Traces the contour lines at a given level and retrieves them for some sort of user-defined
       processing.

SYNOPSIS

       CALL CPCLTR (ZDAT,RWRK,IWRK,CLVL,IJMP,IRW1,IRW2,NRWK)

C-BINDING SYNOPSIS

       #include <ncarg/ncargC.h>

       void c_cpcltr (float *zdat, float *rwrk, int *iwrk,
       float clvl, int *ijmp, int *irw1, int *irw2, int *nrwk)

DESCRIPTION

       The first three arguments are arrays used in the last call to CPRECT, CPSPS1, or CPSPS2, the contents of
       which must not have been changed since that call.

       ZDAT        (REAL  array,  dimensioned as specified in the last call to CPRECT, CPSPS1, or CPSPS2, input)
                   is the data array.

       RWRK        (REAL array, dimensioned as specified  in  the  last  call  to  CPRECT,  CPSPS1,  or  CPSPS2,
                   input/output) is the real workspace array.

       IWRK        (INTEGER  array,  dimensioned  as  specified  in  the last call to CPRECT, CPSPS1, or CPSPS2,
                   input/output) is the integer workspace array.

       CLEV        (REAL, input) is the desired contour level.

       IJMP        (INTEGER, input/output) is initially set to zero by the user. Upon  return  from  CPCLTR,  it
                   will  be  non-zero if coordinates of a contour line segment have been placed in RWRK; it will
                   be zero if all contour line segments at the given level have been generated.

       IRW1        (INTEGER, output) is a pointer to the place in RWRK where X  coordinates  have  been  stored.
                   They will be in RWRK(IRW1+I) for I = 1, 2, ..., NRWK.

       IRW2        (INTEGER,  output)  is  a  pointer to the place in RWRK where Y coordinates have been stored.
                   They will be in RWRK(IRW2+I) for I = 1, 2, ..., NRWK.

       NRWK        (INTEGER, output) is the number of points on the contour line segment. The points  comprising
                   the segment will be (RWRK(IRW1+I),RWRK(IRW2+I)) for I = 1, 2, ... NRWK.

C-BINDING DESCRIPTION

       The C-binding argument descriptions are the same as the FORTRAN argument descriptions.

USAGE

       The  routine CPCLTR may be called at any time after the initialization call to CPRECT, CPSPS1, or CPSPS2.
       It is called using code like the following:

             IJMP=0
         101 CALL CPCLTR (ZDAT,RWRK,IWRK,CLEV,IJMP,IRW1,IRW2,NRWK)
             IF (IJMP.NE.0) THEN
              (PROCESS SEGMENT OF CONTOUR LINE FROM RWRK)
              GO TO 101
             END IF

       CPCLTR is called repeatedly.  Initially, IJMP is zeroed.  Upon each return from CPCLTR, if the  value  of
       IJMP is non-zero, X and Y coordinates have been placed in the real workspace array RWRK and the values of
       IRW1,  IRW2,  and  NRWK  have been set to indicate where the coordinates were put.  After the coordinates
       have been processed, CPCLTR is called again.  If, upon return from CPCLTR, the value of IJMP is zero, all
       contour lines at the specified level have been processed.

       If the parameter 'T2D' has a non-zero value, the contour lines are smoothed, using  cubic  splines  under
       tension.

ACCESS

       To  use CPCLTR or c_cpcltr, load the NCAR Graphics libraries ncarg, ncarg_gks, and ncarg_c, preferably in
       that order.

MESSAGES

       See the conpack man page for a description of all Conpack error messages and/or informational messages.

SEE ALSO

       Online: conpack, cpback, cpchcf, cpchcl, cpchhl, cpchil, cpchll, cpcica, cpclam, cpcldm, cpcldr,  cpcnrc,
       cpdrpl,  cpezct,  cpgetc, cpgeti, cpgetr, cplbam, cplbdr, cpmpxy, cpmviw, cpmvrw, cppkcl, cppklb, cprect,
       cprset, cpscae, cpsetc, cpseti, cpsetr, cpsps1, cpsps2, ncarg_cbind

COPYRIGHT

       Copyright (C) 1987-2009
       University Corporation for Atmospheric Research

       The use of this Software is governed by a License Agreement.

UNIX                                               March 1993                                     CPCLTR(3NCARG)