I have spatial temporal data: Daily measurements of 36 measurement stations for 425 days. I want to do some analysis with these data in R, so I just created a data frame from the data, which looks like this:
For each of the Stations X10004, X10007, ... I have the latitude/longitude values, but I do not know how to add these information correctly to the data frame in order to use the available analysis tools of R.
How to do it? Or should I use other data structure possibilities of R and how?
You need to melt your data into long format, and then merge. Once you've done that, you can use ddply
/data.table
/ggplot
etc.
library(reshape2)
res <- merge(
melt(df, id.vars="date"),
lat.lon,
by.x="variable", by.y="loc.name"
)
head(res)
# variable date value lat lon
# 1 V1 2013-01-01 4 0.6193299 0.815607
# 2 V1 2013-01-02 5 0.6193299 0.815607
# 3 V1 2013-01-03 2 0.6193299 0.815607
# 4 V1 2013-01-04 3 0.6193299 0.815607
# 5 V1 2013-01-05 10 0.6193299 0.815607
# 6 V1 2013-01-06 7 0.6193299 0.815607
In this case, think of variable
as station in your data. And here is the dummy data I created:
df <- cbind(
data.frame(seq(as.Date("2013-01-01"), by="+1 day", length.out=10)),
as.data.frame(replicate(10, sample(1:10)))
)
names(df) <- c("date", paste0("V", 1:10))
head(df)
# date V1 V2 V3 V4 V5 V6 V7 V8 V9 V10
# 1 2013-01-01 4 9 5 10 8 5 7 9 1 1
# 2 2013-01-02 5 10 4 6 6 8 4 6 7 10
# 3 2013-01-03 2 8 1 5 5 3 10 4 9 4
# 4 2013-01-04 3 3 10 4 3 7 9 7 5 5
# 5 2013-01-05 10 6 9 7 10 10 5 5 3 6
# 6 2013-01-06 7 2 2 9 4 2 2 8 8 3
lat.lon <- data.frame(loc.name=paste0("V", 1:10), lat=runif(10), lon=runif(10))
head(lat.lon)
# loc.name lat lon
# 1 V1 0.6193299 0.8156070
# 2 V2 0.3656795 0.9293682
# 3 V3 0.7073155 0.1494767
# 4 V4 0.6715280 0.9029310
# 5 V5 0.3588971 0.2281054
# 6 V6 0.7231073 0.2840767