[R-sig-Geo] SGDF with NA values - SGDF2PCT()

Häring, Tim (LWF) Tim.Haering at lwf.bayern.de
Wed Dec 15 15:46:57 CET 2010

Thank you Michael, your workaround gave me the right hint.
Even though your example didn`t work for me I solved the problem.

# first, I create a colour vector, where dist is a data.frame with red, green, and blue values.
cols <- rgb(dist[,1],dist[,2], dist[,3],alpha=.7)
ind <- data.frame(cols=unique(cols), ix=c(1:length(unique(cols))))

# create a df with coordinate values
pd <- data.frame(x = p$RW, y = p$HW, cols)
# add color-index values to df
pd <- merge(pd, ind, by.x="cols", by.y="cols", all.x=TRUE)

# geoformat
gridded(pd) = ~x+y
pd <- as(pd, "SpatialGridDataFrame")

### plot
g <- grey(0:250/250)
image(hillshade, col=g, axes = TRUE)
image(pd, "ix", col=ind$cols, add=TRUE)

Thanks again.


 Tim Häring
 Bavarian State Institute of Forestry
 Department of Forest Ecology
 Hans-Carl-von-Carlowitz-Platz 1
 D-85354 Freising

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