[R] transparency using plot+points with sp classes

[Uwe Ligges]

This code is not reproducible, hence hard to know if there is a problem 
with R, a contributed package, or what you wrote or did.

Best,
Uwe Ligges

On 28.12.2011 18:07, Ana wrote:
> Hi guys,
> Thansk for the help with the transparency.
>
> I've made some modifications to my code , added rgb in colour to play
> with the transparency and included also a north arrow. I was trying to
> make the code look better, however i am facing another problem, once I
> use symbols with a bg colour. Somehow once I plot the map I loose the
> bg colour info and he gives me only the filled triangle border colour:
>
> arrow<- list("SpatialPolygonsRescale", layout.north.arrow(type=1),
> offset = c(5,10), scale = 2,col="black")
>
> list1=list("sp.points",observations2000,pch=21,col = rgb(red = 0,
> green = 0, blue = 1, alpha = 0.1))
>
> list2=list("sp.points,"observations1999,pch=21,col="blue")
>
> list3=list("sp.points",reference.points,pch=24,col="red",bg="orange")
>
> spplot(polygon_area,"NAME",col="black",col.regions=FALSE, colorkey=FALSE,
>
>         sp.layout=list(arrow,list1,list2,list3),
>
>         scales=list(draw=TRUE),xlab="Longitude",ylab="Latitude", main="Map" )
>
>
>
> On Wed, Dec 28, 2011 at 1:13 PM, Ana<rrasterr at gmail.com>  wrote:
>> How can I make one point graphics with transparency
>>
>> These are all sp classes:
>>
>> plot(polygons_area,axes=TRUE,asp=1.5,main="Title",xlab="Latitude",
>> ylab="Longitude")
>> points(observations2000,type = "p",pch=21,col="green")
>> points(observation1999,type = "p",pch=21,col="blue")
>> points(reference.points,type = "p",pch=21,col="red")
>>
>> how can I add transparency to one of the point graphics, for example
>> points(observation1999,type = "p",pch=21,col="blue")  ?
>
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