FW: [R] Maps and plotting

Shawn Way sway at tanox.com
Thu Oct 14 14:13:33 CEST 2004

Thanks for the help on the translucent dots.  What would be the best
method for creating a map of the facility?  I looked into map* in the
libraries and didn't find anything on creating the maps, just using

Thanks again... 

Shawn Way, PE
Engineering Manager
sway at tanox.com

-----Original Message-----
From: Prof Brian Ripley [mailto:ripley at stats.ox.ac.uk]
Sent: Thursday, October 14, 2004 6:05 AM
To: Barry Rowlingson
Cc: Shawn Way; R-help at stat.math.ethz.ch
Subject: Re: [R] Maps and plotting

On Thu, 14 Oct 2004, Barry Rowlingson wrote:

> Shawn Way wrote:
> >  At our facility we have multiple sample points that are sampled on 
> > any given day.  What I would like to do is create a map of the 
> > facility with the sample points (and point labels) and when we have 
> > out of specification results, place a transparent dot over the area
on the map.
> > As the number of OOS results builds up, I envision the dot getting 
> > darker.
> > 
>   Over what timescale? This sounds like it could be an interactive, 
> real-time on-line monitoring thing. Is it?
>   In which case R's graphics devices might not be good enough, and 
> you'd be better off using a TclTk graphics canvas.
>   library(tcltk) and read the docs!
>   Another idea, if all you are doing is updating a daily image, would 
> be to use a language like Python, and the Python Imaging Library (PIL)

> to draw pretty graphs.
>   I've done something similar that produces daily maps of disease 
> incidence, but I used different size and colour circles and not 
> transparency, so I just used base R graphics and produced a PNG file.
> If I wanted transparency I'd probably use Python/PIL, which can handle

> alpha channels.

I think this may mean *translucent* dots.  R has been able to do
transparent dots for a very long time, but PNG cannot handle
translucency.  On devices (e.g. pdf) which can, you can do this as of R

Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272866 (PA)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595

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