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") ?
On Dec 28, 2011, at 7:13 AM, Ana 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") ?Read the Details section of : ?rgb -- David Winsemius, MD West Hartford, CT
# use the alpha argument of rgb or hsv to create transparent colours
require(sp)
xc <- round(runif(20), 2)
yc <- round(runif(20), 2)
xy <- cbind(xc, yc)
xy.sp <- SpatialPoints(xy)
col1 <- hsv(h = (1:10)/80, v = 0.9, alpha = 0.3)
col2 <- hsv(h = 0.25+(1:10)/50, v = 0.8, alpha = 0.4)
plot(xy.sp[1:10,], pch = 21, col = "red", cex = 20,
bg = col1)
points(xy.sp[11:20, ], pch = 21, col = "darkgreen", cex = 10,
bg = col2)
# Happy Christmas!
Chris Campbell
MANGO SOLUTIONS
Data Analysis that Delivers
+44 1249 767700
-----Original Message-----
From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org]
On Behalf Of Ana
Sent: 28 December 2011 12:13
To: r-help at r-project.org
Subject: [R] transparency using plot+points with sp classes
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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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") ??