On Wed, Sep 24, 2008 at 8:39 AM, Albin Blaschka
<[EMAIL PROTECTED]> wrote:
>
> Dear list,
>
> I would like to apply my own colours to a stacked area plot, done with
> qplot, but I have not succeeded...
>
> What do I have so far (I am dealing with the development of cover of
> specific groups of plants):
>
>
> library(ggplot2)
> library(RODBC)
> channel <- odbcConnect("myusername", case="tolower")
> sql <- "select trial, cover_of, dateofsurvey, cover from mytable"
> mydata <- (sqlQuery(channel, sql))
>
> What I get is the following dataframe (simplified, there are more
> categories, not real data):
>
> trial cover_of dateofsurvey cover
> 1 ZU-316 Cover dead material 2004-09-16 0
> 2 ZU-316 Cover grasses 2004-09-16 16
> 3 ZU-316 Cover herbs 2004-09-16 14
> 4 ZU-316 Cover legumes 2004-09-16 10
> 5 ZU-316 Cover open soil 2004-09-16 30
> 6 ZU-316 Cover dead material 2005-09-18 5
> 7 ZU-316 Cover grasses 2005-09-18 26
> 8 ZU-316 Cover herbs 2005-09-18 14
> 9 ZU-316 Cover legumes 2005-09-18 15
> 10 ZU-316 Cover open soil 2005-09-18 20
> 11 ZU-316 Cover dead material 2006-09-06 7
> 12 ZU-316 Cover grasses 2006-09-06 36
> 13 ZU-316 Cover herbs 2006-09-06 20
> 14 ZU-316 Cover legumes 2006-09-06 15
> 15 ZU-316 Cover open soil 2006-09-06 20
> .
> .
> .
>
> With the following command I get a nice graph (development of cover over the
> years):
>
> qplot(dateofsurvey, cover, data=mydata, geom="area", fill=cover_of,
> main = "Development of cover, ZU-316",
> ylab="projective Cover[%]", xlab = "Year")
>
> As I have those categories (cover grasses, cover herbs...) I would like to
> assign special colours to each (for example "cover grasses" => dark green,
> "cover open soil" => brown ...), but I did not get it so far.
> I tried several variations with area_geom, scale_manual but without
> success...
> For example (which does not work, it just shows the standard colourscheme):
>
> mycolorscheme <- c("khaki", "darkgreen",
> "lightgreen", "yellow", "saddlebrown")
> mycolors <- rep(mycolorscheme,3)
>
> myplot <- qplot(dateofsurvey, wert, data=mydata, geom="area",
> fill=cover_of, main = "Development of cover, ZU-316",
> ylab="projective Cover[%]", xlab = "Year")
> myplot + geom_area(colour = mycolours)
You want to modify the scale (the thing that converts data values to
colours), not the geom:
+ scale_fill_manual(values = mycolorscheme)
(And it's fill you want to change, not colour)
This will also update the legend.
Hadley
--
http://had.co.nz/
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