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From |
"Nick Cox" <n.j.cox@durham.ac.uk> |

To |
<statalist@hsphsun2.harvard.edu> |

Subject |
RE: st: Graphing some Isobars.. |

Date |
Thu, 23 Sep 2004 14:53:30 +0100 |

I agree with Stas. At present, you need to go outside Stata for this. As a geographer and word-nut, I can comment on the terminology here. None of what follows helps solve the problem, or indeed any other problem, so you can bail out here. Isobars are strictly lines of equal (atmospheric) pressure on a map. Contours were originally lines of equal (surface) altitude, but clearly are understood much more broadly. Some geographers have used "isarithm" or "isopleth" as general terms; the latter is perhaps more widespread, and can be contrasted with "choropleth" for maps in which values are shaded by areas (e.g. states or counties). Tukey hit the nail on the head in calling the last "patch maps". A disadvantage of "choropleth" is that many people's memories of studying photosynthesis when young makes them write "chloropleth". In days when some scholars used to show off what Greek they know, or had found in a dictionary, almost every kind of line showing constant values was given a distinct name: some have flourished in limited fields, e.g. isotherm (temperature), isohyet (rainfall), isobath (depth). Some failed to get off the ground, e.g. isonoet (lines of equal IQ), found I believe only in one study of IQ patterns in Tasmania. Nick n.j.cox@durham.ac.uk Stas Kolenikov > Another name I know this under is the countour plot. There are some > routines that go back into prehistoric period of Stata graphics (i.e., > before 8), but they are way too basic. This is a long awaited feature > for me, and so far S-Plus/R is much better in graphs of this kind. Nassar > > I have three variables, X Y & Z (all 3 continuous)... How > can I graph > > 'isobars', ie linkings (x,y) so that Z(x,y) is constant * * For searches and help try: * http://www.stata.com/support/faqs/res/findit.html * http://www.stata.com/support/statalist/faq * http://www.ats.ucla.edu/stat/stata/

**Follow-Ups**:**RE: st: Graphing some Isobars..***From:*"Nassar" <nassar@noos.fr>

**Re: (OT) st: Graphing some Isobars..***From:*"Michael S. Hanson" <mshanson@mac.com>

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