[R] Interesting Behavior in plot()

[Clint Bowman]

I have a 2 by 226200 table, conveniently read in by read.table(), which
exhibits some strange behavior when plotted by plot(V1,V2).  The general
pattern for the range of windspeeds, [0<V1<50] is as expected -- the wind
gust falls in the interval [V1<V2<65] except for certain values of V2.  
For V2 == c(15,26,37,48,59), the V2 values are positioned at one-tenth of 
the V1 (i.e., as if I had issued the command plot(0.1*V1,V2) for just 
those values of V2 -- see attached plot, test.png).  The only other values 
of V2 in the range, 4 and 70, also seem to be affected but aren't well 
enough represented to show up clearly on the plot.

However, if I plot(ws$V1[ws$V2==48],ws$V2[ws$V2==48]), I see the second 
attachment, test2.png, which confirms that the wind speed (V1) really 
should be positioned where one would expect.  I haven't seen any messages 
covering this behaviour and so am looking for an explanation.

I'm running:

> R.Version()
$platform
[1] "i686-pc-linux-gnu"

$arch
[1] "i686"

$os
[1] "linux-gnu"

$system
[1] "i686, linux-gnu"

$status
[1] ""

$major
[1] "1"

$minor
[1] "8.1"

$year
[1] "2003"

$month
[1] "11"

$day
[1] "21"

$language
[1] "R"

on Red Hat 9.0.

TIA,

Clint

-- 
Clint Bowman			INTERNET:	clint at ecy.wa.gov
Air Quality Modeler		INTERNET:	clint at math.utah.edu
Department of Ecology		VOICE:		(360) 407-6815
PO Box 47600			FAX:		(360) 407-7534
Olympia, WA 98504-7600
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