hi all,
I have sent the following programs to Kit Baum, asking him to include
them in the SSC-Archive. I gues that the programs will be available
in the next few days of so. Comments and bug reports would be highly
appreciated.
1) biplot.ado
--------------
Biplot.ado is an upgrade of the program originally written for Stata
5 to Stata 8.2. The upgrade uses the new graphics and adds some
features to the program. Among the new features are Relative
Variation Diagrams, Weights, a data transformation which lets you
interpret the distances in the scatter as mahalanobis distances
(instead of euclidean) and a possibilty for highlighting observations
from different subpopulations.
A more detailed explanation of biplots will be given in my talk on
the German Stata Users' Meeting on April 5th 2004 in Berlin, and
shortly afterwards in the proceedings of that meeting in the
internet.
2) _gmlabvpos.ado
-----------------
_gmlabvpos.ado is an egen function to automatically generate a
variable for the clock-positions of marker labels in scatterplots
(something to include as varname in the option mlabvpos(varname))
The general idea of the program is to not allow the marker labels
interfere with the quantitative information of the marker symbols (as
proposed by Cleveland 1994, Elements of Graphing Data, pg 43). The
program does not try, however, to prevent the marker labels from
overplotting. Therefore the program gives satisfying results only for
scatterplots with just a few observations.
BTW: I wonder if there exist a more general algorithm for clock-
positions. The problem seems to be similar to the labeling of
geographical objects in maps, and there might be a solution from
Geographers which can be applied. However it seems that labels in
maps are placed by hand. If there is no general algorithm, Stata
should probably also offer the possibilty for such placements by
hand. I don't want to have STAGE back, but how about a graphical tool
to build the necassary -generate- and -replace- commands.
many regards
uli
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