4.3 Getting help

Which pchar numbers generate which plotting characters?

In general, there are two ways to get an answer to a question like this. One is to type the physica command


In response, a list of available topics shows up, and you may choose one and type it in at the prompt. A list of subtopics may then appear if there are further subdivisions in your chosen topic. Type them in as needed. To go up a level in the help structure, type a single carriage return key (CR) at the Topic? prompt. Depending on how deep you are, one or several CRs will take you back to the PHYSICA: prompt, while a question mark

Topic? ?

will repeat the list of current subtopics. You may also use

PHYSICA:help graph

to get help on a specific command (graph in this example; also try help introduction). In this case, the same help information is shown, but you are returned back to the PHYSICA: prompt right away.

Alternatively, you may open a hardcopy manual (several copies should be available from your instructor); or use the on-line help facility, the electronic version of the hardcopy manuals.

The only ``exceptions'' to this rule are the five things covered by the display command: fonts, special characters, hatch patterns, line types, and, yes, the plotting characters. For example, to get a table of possible pchar symbols and their codes on your screen you would use display pchar rather than help pchar; the latter simply gives you a brief description of the syntax of the pchar command but not the table of codes.

There are two manuals for physica: one is the User's Guide which takes the same tutorial approach that we have been using here, in much more detail, of course; it guides you by showing many examples. Once you have read the introductory chapters, the best way to use it is to flip through its pages until you find an example that looks like something that you have in mind, and use the commands of that example as an inspiration for generating your own graphs. The other is the Reference Manual which is the detailed description of all commands and their options.

There is one more special manual, PLOTDATA to PHYSICA Conversion Manual, for those users who have macro files written for plotdata, the predecessor program to physica, and wish to convert them to the new physica format.

Returning back to our original question: as an alternative to display pchar you can look up the table of pchar symbols in the Reference Manual on page 83.

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