generate & plot elevation contour lines
my understanding is that adding the "contour = TRUE" will add the contour lines for kriged zinc concentration in the present example. However, what I am after is to superimpose contour lines of elevation in meters above sea level on top of an interpolated variable that is not elevation, eg zinc concentration or some other variable. I have an interpolated maps of an electromagnetic survey (EM38) of a field and I would like to overlay a plot of contour lines to visualize surface drainage patterns. Thanks Karl |---------+----------------------------> | | e.pebesma at geo.uu.| | | nl | | | | | | 27/06/2006 16:55 | | | | |---------+----------------------------> >------------------------------------------------------------------------------------------------------------------------------| | | | To: karl.sommer at dpi.vic.gov.au | | cc: r-sig-geo at stat.math.ethz.ch | | Subject: Re: [R-sig-Geo] generate & plot elevation contour lines | >------------------------------------------------------------------------------------------------------------------------------|
karl.sommer at dpi.vic.gov.au wrote:
Hello list I am making reference to the graph gallery at http://r-spatial.sourceforge.net/gallery I was wondering how one would go about adding elevation contour lines to the example fig08? Presuming that one would have access to a number of geo-referenced elevation measurements with a similar density as the sampling locations indicated with a grey x in fig08. Is there a method to generate contour lines from such information and overlay it onto the existing interpolated graph? Cheers Karl Sommer
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Simpler than I thought it would be: add contour = TRUE to the argument list of spplot. If you want the actual contours, there is a contourLines function that returns them; sp has a function to convert these to SpatialLinesDataFrame objects: contourLines2SLDF(). -- Edzer