Re: st: Why is the legend in xtline limited to 2 to 15?

[Nick Cox <njcoxstata@gmail.com>]

Peeling off the last question: Don't use a legend for one item. Seeing
that reminds me of a certain spreadsheet application, which if I
remember correctly uses by default the legend "Series 1" for one
variable; it doesn't even say "G", or whatever, which in its own terms
would mean something. Use a title or (usually better) a subtitle for
that information; you can just add it yourself.

On the main question:

I am guessing here, but have a look at -help pstyle- for a clue. By
default there are 15 different plotstyles, so I imagine that if you
don't spell out 17 or 20 different ways of showing 17 or 20 different
countries, -twoway- is just going to cycle around the same
possibililities from 16 onwards.  I don't think I've ever tried it.

I am impressed at your optimism that this could work well at all. With
17 or 20 countries,

a. Clearly the country names mean something and you would prefer
seeing them, but a legend with that many entries will take up a large
fraction of your real estate.

b. The plot itself is all too likely to look like a tangled mess.

This is a standard problem, and a difficult one, and all solutions are
wrong from some point of view, but let's try some positives:

0. There's a serious argument, which is hardly novel, that the only
way to do this properly is through an interactive graphic in which
names pop up on demand and the curious reader can interrogate at will.
I leave this on one side because you can't do in Stata. Whether it
would be the answer for Nirina I can't tell.

1. Separating the series, one to a panel, might be tolerable. Names
would be shown better, but clearly you lose out on how easily you can
compare the series. Naturally that's the default for -xtline-. (I
guess that Nirina is using the -overlay- option.)

2. There is a compromise in which every panel contains all the series,
best shown as a backdrop, but each panel highlights just one series.
The main idea occurs in many places, but two that spring to mind are
http://www.stata-journal.com/sjpdf.html?articlenum=gr0046 and
http://www.stata-journal.com/sjpdf.html?articlenum=gr0040 The links
lead to .pdf accessible to all.

3. Do you need all the countries to be identifiable? Sometimes what
works reasonably is to show all and just to identify only a few
countries of greatest interest. We don't know what the research is
here, but it is rare in my experience that every country really needs
individual identification and comment.

Nick
njcoxstata@gmail.com


On 12 March 2014 08:56, Nirina F <fstata@gmail.com> wrote:

> I have panel data and I am graphing a simple line graph through
> years for 17 and then 20 countries with xtline. It looks like the
> legend is only limited to 15 countries so then it reports to me two
> countries under the same legend such as this ---------USA/Luxembourg
> and ______China/Uruguay when I graph 17 countries and then five
> countries under the same legend for 20 countries. do you know how to
> expand it so it is not confusing like this?
>
> Also, when I am just graphing one country
> xtline yvar if Country=="USA", overlay then I do not get the legend
> that that single line is for USA and I do not see any option to add
> legend.
*
*   For searches and help try:
*   http://www.stata.com/help.cgi?search
*   http://www.stata.com/support/faqs/resources/statalist-faq/
*   http://www.ats.ucla.edu/stat/stata/