[R-sig-Geo] makeGrid(PBSmapping)

Markus Loecher loecher at eden.rutgers.edu
Thu Feb 28 21:00:28 CET 2008


Dear geo experts,
I am clearly misunderstanding the role of the projection argument in 
the wonderful utility makeGrid(PBSmapping).
I had hoped that by setting projection ="LL" the resulting grid would 
be equidistant in "real" space, and hence curvilinear in lat/lon space.
But the following code yields the identical, regular grid, 
irrespective of the projection argument:

	mypolys <- makeGrid(x= seq(-123,-122,length=10), y = seq(33, 34, 
length=10), byrow = FALSE, addSID = TRUE, projection = "LL")
	plotMap(mypolys)	
	mypolys <- makeGrid(x= seq(-123,-122,length=10), y = seq(33, 34, 
length=10), byrow = FALSE, addSID = TRUE, projection = 1)
	plotMap(mypolys)

Is there an easy way to create a rectangular grid in lat/lon space ? 
Should I first translate the points to UTM coordinates ?

Thanks!

Markus




More information about the R-sig-Geo mailing list