R help - Oct 2011 - xyplot() or splom()?: two factors from same data frame

I'm not seeing how to plot the quantities associated with two values of a
factor by reading the ?xyplot help page and Deepayan's book. Perhaps I need
to generate many different subsets from the data frame, but that would
require _many_ new data frames.

   The structure of the data frame (for a single stream) has sites (factor),
a date (as.Date), parameters (factor), and quantities (numeric). What I need
to do is produce scatter plots of the quantities associated with two
different parameters conditioned by site or by date (separate plots, I'm
sure).

   I have 24 streams and initially need to look at the relationships of 5
different pairs of parameters (e.g., "Cond" and "TDS") for
all sites and by
sites. Can I do this from the existing data frame?

   It seems to me that a splom() could be ideal for this, but I still have
the question of how to specify quantities for two parameters to plot against
each other.

Rich

Hi Rich

Without  a dataset I am not sure what you need.

Further down the track you will need to plot what you finally need 
and this may help you decide what you need now

for finals try

library(lattice)
library(latticeExtra)

useOuterStrips(
xyplot(variable1 + variable2 ~ Date|Site, data = Data, groups = Groups, ...)
)

this will give you a matrix plot of the columns being the site and 
the rows being the variables.

but for now if you have a large screen you can do a splom by sites 
you may to subset sites.
use par.settings and levelplot settings to reduce the fontsizes etc 
so that you can get as much information

splom( ...|Site, data= Data,...)

if you want to have 2 plots eg  the x axis as time and another 
independent variable
you can plot them on the page together

eg

plot1 <- xyplot(....)
plot2 <- density.plot(...)

print(p1, position= c(0,0,1,0.5), more = T)
print(p1, position= c(0,0.5,1,1), more = F)

see ?print.trellis

As usual everything depends on the data

HTH

Duncan

Duncan Mackay
Department of Agronomy and Soil Science
University of New England
Armidale NSW 2351
Email Home: mackay at northnet.com.au


At 09:41 21/10/2011, you wrote:
>   I'm not seeing how to plot the quantities associated with two values
of a
>factor by reading the ?xyplot help page and Deepayan's book. Perhaps I
need
>to generate many different subsets from the data frame, but that would
>require _many_ new data frames.
>
>   The structure of the data frame (for a single stream) has sites (factor),
>a date (as.Date), parameters (factor), and quantities (numeric). What I need
>to do is produce scatter plots of the quantities associated with two
>different parameters conditioned by site or by date (separate plots, I'm
>sure).
>
>   I have 24 streams and initially need to look at the relationships of 5
>different pairs of parameters (e.g., "Cond" and "TDS")
for all sites and by
>sites. Can I do this from the existing data frame?
>
>   It seems to me that a splom() could be ideal for this, but I still have
>the question of how to specify quantities for two parameters to plot against
>each other.
>
>Rich
>
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