[R-sig-Geo] color category SpatialGridDataFrame SpatialPolygonsDataFrame Corine Land Cover Global Land Cover 2000

[Renaud Lancelot]

Dear Patrick,

I recently met this issue. I finally used image() on the 
SpatialGridDataFrame, defining the appropriate colors using the col 
argument (étonnant, non ;-)). I have defined the legend using legend(), 
and I used split.screen() to arrange the plots. If you wish, I can send 
you the whole stuff (data and code) in a private message (huge datasets).

Renaud

Patrick Giraudoux a écrit :
> Dear all,
> 
> I am wondering what is the safest way to handle colors when 
> SpatialGridDataFrame data are categories. spplot() or image() are 
> extremely convenient when attributes are continuous variables or so (eg 
> altitude, rainfall, etc...), but the colorRamp() system and the 
> col.regions, col arguments, though extremely powerful in other cases, is 
> not really adapted to category data such as Corine LandCover or Global 
> Land Cover 2000 codes. Thus to link pixels to the right color may be 
> quite tedious (however I may have missed something...).
> 
> One option I though about was to change raster into shapefile (or 
> SpatialGrid into SpatialPolygons objects), but again the straight way to 
> get right colors is not evident.
> 
> Any idea ?
> 
> Patrick
> 
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-- 
Renaud Lancelot
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