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graphics bug: type="l" (PR#120)

3 messages · Matthew Wiener, Peter Dalgaard, Brian Ripley

Original
Matthew Wiener
# 
The following commands illustrate a problem with graphing relatively large
data sets using the "line" option to plot:

temp <- runif(200000)  # or whatever other numbers you like;
			# same thing happens with a sine wave
plot(1:200000, temp)    # everything fine
plot(1:200000, temp, type="l")   # data gets cut off


The number of points isn't crucial.  The cutoff point appears to be about
65,000 points.  (70,000 points demonstrates the cutoff; with 50,000 points
there's no cutoff.) 

As far as I can tell, the problem only occurs when using the
option type="l".  It's unaffected by color, line type, and line width.

Matt Wiener



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Peter Dalgaard
# 
mcw@ln.nimh.nih.gov writes:
Doesn't happen to me with 0.63.pre-3 on RedHat Linux. I can't offhand
see any documented fixes that would affect this, perhaps there's an OS
difference? Looks a bit like a short integer overrun (65536=2^16)
Brian Ripley
#
On Tue, 16 Feb 1999 Matt Wiener, mcw@ln.nimh.nih.gov wrote:

            

      
      
      
    

        
This is device-specific (and which device was not mentioned). It does not
happen on Windows (rw0632) nor on a postscript device. It does happen on
the Unix x11() device for me, and my guess is that it is a limitation in
the X library used.  (Not in the X server, for this works in gs
displaying postscript, and in S-PLUS. The lines are drawn in a single Xlib
call.)

Do you really want to plot such a dataset in one go? What do you
expect to see of significance in 200000 points? (There are by default only 
about twice that many pixels on the device surface.) Are they really one
group? Would some group colour coding help? ....