[R-sig-Geo] followup on rgdal - invalid alignment error

[Roger Bivand]

On Fri, 8 Sep 2006, Scott W Mitchell wrote:

> After sending my last post, detailing my system setup with a working  
> R/GDAL/rgdal installation on a Mac, I played a bit more and came  
> across a glitch when I tried example(readGDAL) on the fresh build.

Scott:

Thanks very much for your detailed descriptions, and I hope updating to 
try to help the original questioner hasn't broken things you need now.

> 
> It gets through translating the data set and the image command, but  
> then on summary() I get:

Can you re-run the example code by hand, line by line (copy & paste for
example)? From what you write, image displays correctly, is that right?  
That suggests that the data has been read correctly, otherwise it would
not have displayed? Which image is this - several are read in the example?  
Does example(GDAL.open) run smoothly? Something in the first band of the
data is causing sort to choke, could it be an NA? can you copy out the 
band to a regular vector, and save it to file as an R object? If it is a 
value in the band, it should be saved in a platform independent way. GDAL 
also swaps to suit endianness.

Roger

> 
> rdGDAL> summary(x)
> 
> *** caught bus error ***
> address 0x17, cause 'invalid alignment'
> 
> Traceback:
> 1: sort(x, partial = unique(c(lo, hi)))
> 2: quantile.default(object)
> 3: stats::quantile(object)
> 4: summary.default(X[[1]], ...)
> 5: FUN(X[[1]], ...)
> 6: lapply(as.list(object), summary, maxsum = maxsum, digits =  
> 12,     ...)
> 7: summary.data.frame(object at att)
> 8: summary(object at data)
> 9: summary(object at data)
> 10: summary(x)
> 11: summary(x)
> 12: eval.with.vis(expr, envir, enclos)
> 13: eval.with.vis(ei, envir)
> 14: source(zfile, local, echo = echo, prompt.echo = prompt.echo,      
> verbose = verbose, max.deparse.length = 250, encoding = encoding)
> 15: example(readGDAL)
> 
> Possible actions:
> 1: abort (with core dump)
> 2: normal R exit
> 3: exit R without saving workspace
> 4: exit R saving workspace
> Selection:
> 
> A byte-ordering issue???
> 
> Any suggestions?
> 
> Scott
> 
> 
> 
> 
> ----
> Scott Mitchell, Assistant Professor, Carleton University
> Department of Geography & Environmental Studies, Loeb B443A
> & Geomatics and Landscape Ecology Research Laboratory, Nesbitt 340
> Mailing:  Loeb B349, 1125 Colonel By Dr., Ottawa, ON K1S 5B6 Canada
> +1-613-520-2600 x2695 Fax: +1-613-520-4301 Scott_Mitchell at carleton.ca
> 
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> 

-- 
Roger Bivand
Economic Geography Section, Department of Economics, Norwegian School of
Economics and Business Administration, Helleveien 30, N-5045 Bergen,
Norway. voice: +47 55 95 93 55; fax +47 55 95 95 43
e-mail: Roger.Bivand at nhh.no