1.1 Introduction

The GRPH2 high-level package for graphics processing is a collection of routines for drawing graphics such as coordinate axes and contour lines by combining simple graphics elements such as polylines and characters in GRPH1.

The GRPH2 is a level-2 library and is not machine-dependent, but you will need to have GRPH1, MISC1, and MATH1 properly installed. (Strictly speaking, finding a file name for storing map information used by UMPACK may be system-dependent.) For definitions of basic terminology for coordinate systems, coordinate transformations, and the output primitives, see the manual for "GRPH1."

The GRPH2 contains several sub-packages corresponding to the different types of graphics to be drawn. The number of sub-packages have increased gradually over the years, and at the present, the following packages are available for creating graphs for presenting 1-D scalar quantities, 2-D scalar quantities, and 2-D vector quantities.

GRPACK
Controls functions such as page break, and performs initialization.
UXPACK, UYPACK, UZPACK, ULPACK, UCPACK
Draws coordinate axes. The sub-packages have the following functions.
- UXPACK/UYPACK: Coordinate axes for Cartesian coordinates
- ULPACK: Logarithmic coordinate axes
- UCPACK: Coordinate axes for date
- UZPACK: Handling coordinate axis parameters
UUPACK/UVPACK/UHPACK
Polylines, markers, and bar graphs
- UUPACK: Graph with coordinated X and Y axes and parameter settings.
- UVPACK: Graphs with independent variables for X axis and dependent variables for Y axis.
- UHPACK: Graphs with independent variables for Y axis and dependent variables for X axis.
USPACK
Auto-scaling and simple coordinate axis routines.
UDPACK, UEPACK, UGPACK, UWPACK
Drawing graphics for 2-D quantities. The sub-packages have the following functions.
- UDPACK: 2-D contours
- UEPACK: 2-D tones
- UGPACK: 2-D vector fields
- UWPACK: Handling grid point data
Of these, the UDPACK and UEPACK draw graphics in the U-coordinate, so they are compatible with all normalization transformations supported by GRPH1. On the other hand, the UGPACK draws graphics in the V-coordinate in the present version, so it can only be used for the Cartesian coordinate (ITR=1-4).
UMPACK
Draws map information (such as coastlines and longitude and latitudes lines).
UFPACK, UBPACK
Draw graphic elements. The sub-packages have the following functions. In dcl-ver. 5, the subroutine group with the below functions have been included in the GRPH1 level, so they will be removed from future versions.
- UFPACK: Arrows
- UBPACK: Labeled polylines

Many packages in GRPH2 have independent internal-variable-handling routines with the name xxpGET/xxpSET. Here, xx is the first two characters of the package name, and p is the variable type (R: floating-point variable; I: integer variables; L: logical variables; and C: character variables. In this manual, the entry name for different types will be collectively referred to as xxpGET/xxpSET.