[R] Normal score transform of spatial data

Thomas Adams Thomas.Adams at noaa.gov
Fri Jul 28 19:58:15 CEST 2006


I have 2 related questions:

(1) first I have x-y-z data, where x & y are the geographic locations of 
point values, z. I need to perform a normal score transform on the 
z-values and maintain their geographic location. So, how do I go from 
columns x-y-z to x-y-z-t (or x-y-t), where the t-values are the normal 
score transforms of the z-values? Can I use qnorm(ppoints(data)) to do 
this; how?

(2) I also need to do a reverse transform of a matrix of normal score 
values (v) to my original data value units; I have seen that I can use 
something like approx(t, x, v)$y. Again, the matrix represents a spatial 
grid. So, how do I maintain the same spatial ordering resulting from the 
reverse transform?

Thank you for your help.


Thomas E Adams
National Weather Service
Ohio River Forecast Center
1901 South State Route 134
Wilmington, OH 45177

EMAIL:	thomas.adams at noaa.gov

VOICE:	937-383-0528
FAX:	937-383-0033

More information about the R-help mailing list