I want to create a map kind of like this:
I interpolated the data and then plotted it using filled.contour()
As you can see, the map is not plotting correctly. I need to find a way to convert the output back into latitude and longitude so that the map will plot correctly. How do I do this?
I checked out this forum: Plotting interpolated data on map but it doesn't answer my question.
Code for map:
df <-read.table("Petra_phytoplankton+POM_xydata_minusNAs_noduplicates.txt",header=T)
attach(df)
names(df)
fld <- with(df, interp(x = longitude, y = latitude, z = d13C))
filled.contour.ungeoreferenced<-(filled.contour(x = fld$x,
y = fld$y,
z = fld$z,
color.palette =
colorRampPalette(c("blue", "green","yellow","orange","red")),
xlab = "Longitude",
ylab = "Latitude",
key.title = title(main = "d13C", cex.main = 1)))
map(add=TRUE, fill=TRUE)
FYI here is a snippet of my dataset:
latitude longitude d13C
-65 -70 -27.7
-61 150 -32.2
-61 150 -28.3
-60 116 -26.8
-60 116 -24.7
-47 38 -24.8
-38 150 -20.5
19 -65.7 -19.9
19 -65.5 -18.5
18 -60.7 -20
18 -58.5 -18.2
18 -57.8 -19
17 -55.4 -18.6
17 -50.8 -18
17 -47.1 -18.3
17 -45.5 -19.4
16 -43.3 -17.9
15 -40.7 -18.5
14 -39.3 -19.9
12 -36.7 -19.9
12 -36.2 -19.9
11 -34.4 -19.2
10 -32 -18.5
9 -30.3 -19.3
8 -29.2 -19.4
7 -26.6 -18.2
7 -25.5 -19.3
6 23.9 -20
3 -21.3 -20.4