Appendix B. PGPLOT Symbols

B.1 Character Encoding

The PGPLOT routines that display text, e.g., PGTEXT, PGMTXT, and PGMTXT, generate a visible representation of the characters supplied in a Fortran character variable or constant. On most computer systems, a Fortran character can take any of 256 values, numbered 0-255 (decimal). PGPLOT interprets the values as follows:
These are used for the standard graph markers. On most computer systems, they are non-printable control characters.
PGPLOT interprets these according to the US-ASCII character set, a subset of the ISO-Latin character sets, with one exception: character number 94, which should be a circumflex (^), is displayed as a degree symbol (°). The degree symbol is also available as character 176, which should be used in preference; eventually the display of character 94 will be corrected.
These are unassigned; in the ISO-Latin character sets, they are reserved for non-printable control characters.
As far as possible, PGPLOT interprets these according to the ISO-Latin-1 character set. In some cases, required accents are omitted. I hope to rectify the omissions in a later version of PGPLOT. Note that if your computer system does not use the ISO-Latin-1 character set, the output of a PGPLOT program will not correspond to the characters in the source code.
The complete character encoding is displayed in Figure B.0. This is for the standard PGPLOT roman font (font number 2); some of the symbols will differ from font to font.

B.2 Additional Symbols

An escape code allows a large number of additional symbols to be displayed by PGPLOT. Each symbol is composed of a set of vectors, based on digitized type fonts devised by A. V. Hershey of the US Naval Postgraduate School, and is assigned a number in the range 0-4000.

Figures B.1 to B.7 show the graphical representation of all the available symbols arranged according to Hershey's numerical sequence; the blank spaces in this table represent ``space'' characters of various widths. Note that not every number has an associated character. Any character can be inserted in a text string using an escape sequence of the form \(nnnn), where nnnn is the 4-digit Hershey number.

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Tim Pearson, California Institute of Technology, tjp·
Copyright © 1996 California Institute of Technology