Hershey names a repertoire, not one universal desktop font
Windell Oskay’s firsthand Hershey Text development account traces its selected alphabets to A. V. Hershey’s government work in the 1960s and later coordinate-table distribution. The historical characters use line segments, and implementations may rename or select only part of that repertoire. This guide concerns those vector resources, not the chocolate brand’s wordmark. For the general difference between stroke and outline construction, read single-line fonts; the separate task here is identifying the particular implementation and character mapping.
In IDL, choose the vector system and then the numbered face
NV5’s IDL 9.3 documentation identifies Font 3 as Simplex Roman. Direct Graphics selects the vector system with FONT=-1; embedded formatting then chooses a numbered face. Its documented example uses !8 for Complex Italic, whereas IDL Graphics functions use a font name such as Hershey 8. Do not confuse the vector-system switch with the selected face number. Generate a specimen with SHOWFONT before using a Greek symbol: the manual explicitly warns that its Greek keyboard mapping differs from Windows Symbol. Preserve the intended symbol as a written note beside the program-specific code.
In GNU plotutils, use its own family names and character maps
The GNU plotutils manual instead lists names such as HersheySerif, HersheySans and HersheyScript, along with separate symbol resources. Its plotfont utility creates a character map for a font available in the selected output format. For a scientific figure, record the plotting program, output device and complete font name, then inspect the actual title, axis labels and symbols together. Do not copy an IDL number into another program expecting the same result. The homepage Unicode text options change characters in copied text; they do not select a plotting engine’s built-in Hershey font or translate its legacy symbol mapping.
Your questions, answered.
Is every Hershey font selected by the same number?
No. IDL documents its own numbered faces, while GNU plotutils uses named resources. Keep the application and selection method attached to the specimen.
Can I assume a Greek symbol uses the same key as Windows Symbol?
No. IDL’s documentation explicitly gives different mappings. Inspect that implementation’s character table before labeling a scientific figure.
Sources & background
Sources supporting this page’s explanations. Practical examples are our editorial suggestions.