Dear useRs,
I'm trying to plot spray quantities against dates, and label the points
on the plot. Basically quite simple, but sometimes two chemicals have
been used and are listed in separate rows in the table as below; then
the labels are written on top of each other.
> spray
SprayDate PD Trt Qwater Qai
1 2005-03-09 Spidermites Pegasus 1300 1.04
2 2005-03-10 Powdery MKP 800 0.40
3 2005-03-10 Powdery Nimrod 250 EC 800 2.40
4 2005-03-12 Spidermites Pegasus 1300 1.04
5 2005-03-16 Spidermites Pegasus 1300 1.04
6 2005-03-17 Powdery Stroby 50 WG 800 0.40
7 2005-03-21 Spidermites Dynamec 1.8 EC 1250 0.62
8 2005-03-21 Spidermites Apollo 50 SC 1250 0.62
9 2005-03-30 Whiteflies Pegasus 1000 0.60
I came up with the work around below which gave me my plot for some of
the data (despite warnings). The idea was to split the second chemical for each
date into
a separate file and plot the text a little higher:
> spray1 <- spray[spray$PD=="Spidermites", ]
> spray2 <- spray1[spray1$SprayDate==unique(spray1$SprayDate), ]
Warning message:
longer object length
is not a multiple of shorter object length in: spray1$SprayDate ==
unique(spray1$SprayDate)
> spray3 <- spray1[spray1$SprayDate!=unique(spray1$SprayDate), ]
Warning message:
longer object length
is not a multiple of shorter object length in: spray1$SprayDate !=
unique(spray1$SprayDate)
> plot(as.Date(spray2$SprayDate), spray2$Qwater,
+ xlim = c(as.Date("2005-03-08"), as.Date("2005-03-24")), ylim = c(0,1500))
NULL
> text(as.Date(spray2$SprayDate), spray2$Qwater,
+ labels = spray2$Trt, pos = 4, srt = 45)
NULL
> text(as.Date(spray3$SprayDate), spray3$Qwater+100,
+ labels = spray3$Trt, pos = 4, srt = 45)
NULL
But it didn't work for everything:
> spray1 <- spray[spray$PD=="Powdery", ]
> spray2 <- spray1[spray1$SprayDate==unique(spray1$SprayDate), ]
Warning message:
longer object length
is not a multiple of shorter object length in: spray1$SprayDate ==
unique(spray1$SprayDate)
> spray2
SprayDate PD Trt Qwater Qai
2 2005-03-10 Powdery MKP 800 0.4
> spray3 <- spray1[spray1$SprayDate!=unique(spray1$SprayDate), ]
Warning message:
longer object length
is not a multiple of shorter object length in: spray1$SprayDate !=
unique(spray1$SprayDate)
> spray3
SprayDate PD Trt Qwater Qai
3 2005-03-10 Powdery Nimrod 250 EC 800 2.4
6 2005-03-17 Powdery Stroby 50 WG 800 0.4
Does anyone have a better way of splitting the second reading for each
date off, or another way of printing two labels for one plotted point?
Any help would be greatly appreciated.
cheers,
Lisbeth
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