[R] Maps and plotting

Shawn Way sway at tanox.com
Thu Oct 14 14:13:10 CEST 2004

Thank you very much..  It seems that the points problem is fairly easy
to solve, I just need to work on the mapping..

Thanks again... 

Shawn Way, PE
Engineering Manager
sway at tanox.com

-----Original Message-----
From: Barry Rowlingson [mailto:B.Rowlingson at lancaster.ac.uk] 
Sent: Thursday, October 14, 2004 5:42 AM
To: Shawn Way
Cc: R-help at stat.math.ethz.ch
Subject: Re: [R] Maps and plotting

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.


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