[R] Legend (guides) for point and two line graph

[David Bourne]

I’m trying to generate a plot with a series of data points and best fit lines from two stat models. I’m generating the best-fits with another program. I have the data in a csv file as:

Time,Observed,Calculated,Model
0.000,0.00000,13.0810,1C
0.2500,15.0000,12.5298,1C
0.5000,12.0000,12.0018,1C
1.000,9.00000,11.0117,1C
2.000,8.00000,9.26969,1C
4.000,6.50000,6.56882,1C
6.000,4.80000,4.65489,1C
9.000,3.20000,2.77680,1C
12.00,2.10000,1.65641,1C
18.00,1.80000,0.589422,1C
24.00,0.900000,0.209736,1C
0.000,0.00000,21.7130,2C
0.2500,15.0000,15.0512,2C
0.5000,12.0000,11.8203,2C
1.000,9.00000,9.29374,2C
2.000,8.00000,7.82242,2C
4.000,6.50000,6.20213,2C
6.000,4.80000,4.93346,2C
9.000,3.20000,3.50010,2C
12.00,2.10000,2.48310,2C
18.00,1.80000,1.24979,2C
24.00,0.900000,0.629039,2C

I read in the data with (R 3.1.1 GUI 1.65 Mavericks build (6784)):

>rtest <- read.csv("rtest.csv",header=TRUE)

Checked with

>rtest
    Time Observed Calculated Model
1   0.00      0.0  13.081000    1C
2   0.25     15.0  12.529800    1C
3   0.50     12.0  12.001800    1C
4   1.00      9.0  11.011700    1C
5   2.00      8.0   9.269690    1C
6   4.00      6.5   6.568820    1C
7   6.00      4.8   4.654890    1C
8   9.00      3.2   2.776800    1C
9  12.00      2.1   1.656410    1C
10 18.00      1.8   0.589422    1C
11 24.00      0.9   0.209736    1C
12  0.00      0.0  21.713000    2C
13  0.25     15.0  15.051200    2C
14  0.50     12.0  11.820300    2C
15  1.00      9.0   9.293740    2C
16  2.00      8.0   7.822420    2C
17  4.00      6.5   6.202130    2C
18  6.00      4.8   4.933460    2C
19  9.00      3.2   3.500100    2C
20 12.00      2.1   2.483100    2C
21 18.00      1.8   1.249790    2C
22 24.00      0.9   0.629039    2C

Generated the graph with:

ggplot(rtest, aes(x=Time, y=Calculated,color=Model, group=Model)) + geom_line(aes(size=2)) + geom_point(aes(y=Observed, size=Observed), size=6, colour="black") + scale_colour_manual(values=c("green","red")) + labs(size="Observed”)

Which resulted in the plot:

http://www.boomer.org/rtest/rtest.pdf

I’d like to:

1) get rid of the Observed / 2 legend(guide)
2) maybe keep the Observed and have a circle, i.e., loose the ‘2’
3) understand how to create, format the legend

This seems like a common enough problem but the online documentation, R for Dummies nor the R Graphic Cookbook seems to have an answer (from my reading).

Thanks for any clues/suggestion.

David