1 Introduction

The National Center for Atmospheric Research in Boulder, Colorado has, for many years, distributed a extensive suite of high level graphics utilities. When NCAR converted these utilities to run over the ISO standard GKS, Starlink was used as a test site. Starlink was subsequently given permission to release the NCAR utilities as part of the Starlink Software Collection. The NCAR utilities offer an alternative high level graphics package to PGPLOT (SUN/15) for use within Starlink applications. The NCAR package is arguably more powerful than PGPLOT in functionality and flexibility, but it does require a little more time to master. Starlink provides a set of extensions to the NCAR graphics utilities, SNX (SUN/90), to make the use of NCAR more accessible to the beginner. For lower level work, SGS (SUN/85) or GKS (SUN/83) should be used.

The utilities provided by NCAR are:

AUTOGRAPH
— Draws and annotates curves or families of curves.
CONRAN
— Contours irregularly spaced data labelling the contour lines.
CONRAQ
— Like CONRAN, but faster because it has no labelling capability.
CONRAS
— Like CONRAN, but slower because lines are smoothed and crowded lines are removed.
CONREC
— Contours two dimensional arrays, labelling the contour lines.
CONRECQCK
— Like CONREC, but faster because it has no labelling capability.
CONRECSUPR
— Like CONREC, but slower because lines are smoothed and crowded lines are removed.
DASHCHAR
— Software dashed line package with labelling capability.
DASHLINE
— Like DASHCHAR, but faster because it has no labelling capability.
DASHSMTH
— Like DASHCHAR, but slower because lines are smoothed.
DASHSUPR
— Like DASHCHAR, but slower because lines are smoothed and crowded lines are removed.
EZMAP
— Plots continental and/or national and US state boundaries in one of nine map projections.
GRIDAL
— Package for drawing graph paper, axis, etc.
HAFTON
— Draws halftone (greyscale) picture from a two dimensional array. (N.B. The GKS cell array function GCA should be used on devices with a true greyscale capability.)
HSTGRM
— Plots histograms.
ISOSRF
— Plots iso-values surfaces (with hidden lines removed) from a three dimensional array.
ISOSRFHR
— Plots iso-values surfaces (with hidden lines removed) from a high resolution three dimensional array.
PWRITX
— Plots high quality software characters.
PWRITY
— Plots simple software characters.
PWRZI
— Draws characters in three-space, for use with the ISOSRF utility.
PWRZS
— Draws characters in three-space, for use with the SRFACE utility.
PWRZT
— Draws characters in three-space, for use with the THREED utility.
SRFACE
— Plots a three dimensional display of a surface (with hidden lines removed) from a two dimensional array.
STRMLN
— Plots a representation of a vector flow of any field for which planar vector components are given on a regular rectangular lattice. 1
THREED
— Provides a three space line drawing capability.
VELVCT
— Draws a two dimensional velocity field by drawing arrows from the data locations.

The NCAR graphics utilities are released exactly as supplied by NCAR except that the default behaviour of AUTOGRAPH and HSTGRM has been changed to not clear the screen after each plot — this is more appropriate for an interactive environment.

Because of a name conflict with a Fortran run-time library routine on UNIX, the NCAR routine FLUSH has been removed from the UNIX release of the NCAR library. In order to get the same behaviour as a call to FLUSH when using NCAR, the call

         CALL PLOTIT( 0, 0, 2 )

may be used (see the SPPS description in the NCAR manual).

1Note: because of portability problems this utility is not available on UNIX.