Mysterious (to me) behaviour of cbind() on an envelope -- ASDAR ch. 7

Dear r-sig-geo friends:

I am working through ASDAR (Applied Spatial Data Analysis with R) book 
using the code and datasets on the book's website 
http://www.asdar-book.org/.

In sppa_mod.R (code for Chapter 7) we are trying to bind a new column 
giving the point-pattern name to an object of class envelope:

 Gresults <- rbind(envjap, envred, envcells)
 class(Gresults)
[1] "envelope"   "fv"         "data.frame"
 Gresults <- cbind(Gresults, DATASET=rep(c("JAPANESE", "REDWOOD", "CELLS"), each=length(r)))
but somehow the newly-bound column does not get the assigned name 
'DATASET', but is assigned the name 'y':
Thanks for noting this. I've updated the online code to give the variable 
the name "y" instead of "DATASET" here, and in the F and K tests too. An 
erratum has also been added. The figures now show the envelopes as on book 
figures 7.3, 7.4 and 7.9. There was a further infelicity in that 
lpolygon() takes a col= rather than a fill= argument, changed in the 
online code for the figures.

Best wishes,

Roger

str(Gresults)
Classes 'fv' and 'data.frame':  144 obs. of  6 variables:
$ r   : num  0 0.005 0.01 0.015 0.02 0.025 0.03 0.035 0.04 0.045 ...
$ obs : num  0 0 0 0.0615 0.0615 ...
$ theo: num  0 0.00509 0.02021 0.04491 0.07843 ...
$ lo  : num  0 0 0 0 0 ...
$ hi  : num  0 0.0625 0.0748 0.1427 0.1933 ...
$ y   : Factor w/ 3 levels "CELLS","JAPANESE",..: 2 2 2 2 2 2 2 2 2 2 ...
....

somehow the envelope has been removed also. Then when I try to plot according to the following code:

print(xyplot(obs~theo|DATASET , data=Gresults, type="l", ...
the classifying category is not found. If I replace DATASET with y the plot is shown as in Fig. 7.3.

Clearly the cbind() is somehow not preserving the assigned column name, despite the class being build on data.frame. Where it gets the 'y' from is also seriously mysterious to me.

Here's my version info. I started from a clean workspace and only loaded the packages as indicated.

version
platform       x86_64-apple-darwin9.8.0
arch           x86_64
os             darwin9.8.0
system         x86_64, darwin9.8.0
status
major          2
minor          14.0
year           2011
month          10
day            31
svn rev        57496
language       R
version.string R version 2.14.0 (2011-10-31)

Package:            sp
Version:            0.9-94
Date:               2011-12-21

Package:            spatstat
Version:            1.25-2
Date:               2012-01-19

Thanks for any insight!

D. G. Rossiter
Senior University Lecturer
University of Twente, Faculty ITC
Hengelosestraat 99
PO Box 217, 7500 AE Enschede, the Netherlands (NL)
Phone:  +31-(0)53 4874 499
Fax:    +31-(0)53 4874 336
mailto:rossiter at itc.nl,  Internet: http://www.itc.nl/personal/rossiter

Faculty of Geo-Information Science and Earth Observation (ITC)
University of Twente
Chamber of Commerce: 501305360000

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Mysterious (to me) behaviour of cbind() on an envelope -- ASDAR ch. 7

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