# [Rd] Strange behaviour of image (PR#510)

**Peter Dalgaard BSA
**
p.dalgaard@biostat.ku.dk

*06 Apr 2000 20:47:44 +0200*

J.C.Rougier@durham.ac.uk writes:
>* The following commands
*>*
*>* z <- matrix(seq(0, 1, len=1000))
*>* image(z, 1, z, zlim=c(0, 1), col=gray(1:10/10))
*>*
*>* appear to violate the image functionality as described on the
*>* help page. As I understand it, by specifying a zlim of c(0, 1)
*>* and a colour vector of length 10, the colours should correspond
*>* to the intervals (0, 0.1), (0.1, 0.2), ..., (0.9, 1.0), this
*>* being 10 equally-spaced intervals on (0, 1). It is clear from
*>* the image that this has not occurred. In fact the intervals are
*>* apparently (0, 1/18), (1/18, 3/18), ..., (15/18, 17/18), (17/18,
*>* 1). Have I misunderstood something?
*
I don't see that anything else is being promised...
If someone actually thought about this, then the choice might be
related to the behavior at peaks and troughs. (since a circle with
radius r looks wide compared to the region between two circles with
diameter n*r and (n+1)*r)
--
O__ ---- Peter Dalgaard Blegdamsvej 3
c/ /'_ --- Dept. of Biostatistics 2200 Cph. N
(*) \(*) -- University of Copenhagen Denmark Ph: (+45) 35327918
~~~~~~~~~~ - (p.dalgaard@biostat.ku.dk) FAX: (+45) 35327907
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