newbie bbox type question

I want to have one map (via writeOGR) which has the whole thing, and then have several maps by days.

However, I want the whole area as defined by the entire data set to show every day.

I looked at bbox but I can't set a bbox.

I think the problem here is that writeOGR doesn't create maps, it
creates data files.

 If you wnt to create a map plot that is based on the bbox of a given
sp object, you can set up an empty plot from its bbox this way:

 > plot(SpatialPoints(t(bbox(m))),cex=0)

 two things to note: I use cex=0 so the points dont show up (because
type="n" doesnt work) and the bbox is transposed because of the way
its rows and columns are arranged.

 Then you can add stuff to the plot area, eg the first polygon:

 > plot(m[1,],add=TRUE)

Not sure if this is what you are really after since its not clear what
your 'map' is and where writeOGR fits into this...

Barry