R help - Mar 2006 - Converting shapefiles to use in contour plots

Dear R-users,

I have imported a shapefile with depth contours for a sea:

depths<-read.shape("D://My Documents/BarentsSea.shp",dbf.data=T)

(This is in mercator projection)

**Is there a way to convert this shapefile into a format that it may be
plotted on a contour plot?**

I wish to add these contours onto a map (already coded using 'maps'
package) to map the sea contours with surrounding coastlines and answers
to my previous question (thankyou to everyone for that) seem to suggest
that using contour plot is the way to go.

Thankyou again,

Lillian.

-- 
Lillian Sandeman
PhD Student
School of Biological Sciences
University of Aberdeen
AB24 2TZ

Tel.: 01224 272648
E-mail: l.sandeman at abdn.ac.uk