Re: [Plplot-general] Fwd: PLplot capabilities

[Alan W. I. <ir...@be...>]

On 2017-09-27 17:34+0900 Don Warren wrote:

> This is either a feature request or "RTFM"-bait.  I'm trying to figure out
> if PLplot can do the following two things:
> 
> (1) Logarithmic ticks on an axis, but only labeling every Nth decade (when
> your Y axis goes from 10^-60 to 10^-20, you don't want every single decade
> to have a number next to it!)
> 
> (2) Moving tick mark numbers towards/away from the axis they're associated
> with.  It looks like PLplot can do this with the axis labels, using the
> plmtex command.  Is there no way to do this with the numbers associated
> with major tick marks?
> 
> I know both of these could be done by hand with sufficient usage of the
> plmtex command (or rather, I know how to do it in PGPLOT, which I'm
> currently stuck using for legacy reasons).  But then I am individually
> labeling each major tick on the axis, and placing them all independently.
> I would rather not have 20 extra "annotation" blocks in my plotting scripts
> if it's avoidable, not to mention the time spent making sure each number is
> correctly positioned.

Hi Don:

This is my second attempt to answer you since the first attempt sent
earlier today did not appear to be distributed to the mailing list....

Sorry we didn't respond the first time you asked your questions, but I
will attempt to do that now.

Note, I give you a number of plplot.org references below, but you will
have to wait to access those because of a general Sourceforge outage
that started today for the many websites they supply for projects
(like ours) that they host.  Apparently they are working hard to
fix whatever the issue is, but there is no ETA about when SF-related
websites like ours will be available again.

With regard to your question (1), PLplot does have detailed log axis
labelling (the plbox "l" option) to do that, but that is only
suitable for data whose range is a couple of decades (see
<http://plplot.org/examples.php?demo=04> for an example of
that capability) where you want to label unequally spaced logarithmic
subticks between the decades, corresponding to 1, 2, 3, etc., times
some power of 10.  So for your huge range in data, instead of using
that option, I suggest you simply take the log_10 of your data and use
ordinary labelling of those equally spaced major and minor tickmarks
where you have the choice of both the major and minor equally spaced
tick intervals.  See
<http://plplot.org/docbook-manual/plplot-html-5.12.0/plbox.html>
for more details.

With regard to your question (2), I don't think PLplot currently has
this capability.  However, our users appear to be satisfied with the
current positioning of numerical axis labels, and that might turn out
to be true for you as well once you try PLplot. So to evaluate the spacing we 
provide
(even before you try PLplot) I suggest you look carefully at the
tick-mark labelling results for our many standard examples at
<http://plplot.org/examples.php>.

Alan
__________________________
Alan W. Irwin

Astronomical research affiliation with Department of Physics and Astronomy,
University of Victoria (astrowww.phys.uvic.ca).

Programming affiliations with the FreeEOS equation-of-state
implementation for stellar interiors (freeeos.sf.net); the Time
Ephemerides project (timeephem.sf.net); PLplot scientific plotting
software package (plplot.sf.net); the libLASi project
(unifont.org/lasi); the Loads of Linux Links project (loll.sf.net);
and the Linux Brochure Project (lbproject.sf.net).
__________________________

Linux-powered Science
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