Nick Winter <[email protected]>, using Stata 8, asks about getting a
fixed number of unlabeled ticks between his labeled ticks,
> [...] is there no longer any automated way to get Stata 8 to handle
> axes the way Stata 7 did by default: that is, range from data min to
> max, min and max labeled, with five tick marks evenly spaced from
> min to max. The first two are easy, with the -xlab(minmax)- and
> -ylab(minmax)- options.
>
> However, the tick marks aren't so easy, [...]
In Stata 8 graphics, the positions of major labels and ticks, options
[x|y]label() and [x|y]tick()), are specified over the whole range of the x- or
y-axis. Minor labels and ticks, options [x|y]mtick() and [x|y]mlabel(), can
also be specified at positions between the major and ticks using the #<#>
rule, see -whelp axis_label_options-. Taking Nick's example, we can add three
minor x-axis ticks, placing them equally spaced between the minimum and
maximum labeled ticks, using the -xmticks- option,
. sc mpg price , xlab(minmax) xmticks(##4)
If Nick does not like that the minor ticks are shorter than the labeled ticks,
he can specify their length with the suboption tlength(),
. sc mpg price , xlab(minmax) xmticks(##4, tlength(scheme tick))
That was a bit unfair. I used an undocumented feature of named styles that
allows an indirect reference to settings in the current graphics scheme to be
used in place a style name or explicit value. Most graphics schemes define a
default major tick length and that length is defined under the name -tick-, so
by specifying -tlength(scheme tick)- we were requesting the default major tick
length specified in the current scheme file.
Alternately, Nick could type
. sc mpg price , xlab(minmax) xmticks(##4, tlength(tiny))
to specify that the minor tick length is -tiny-, though settling on -tiny-
might require some experimentation.
-- Vince
[email protected]
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