Dear all
I have done GIS in ggmap package :
map=get_map(location=c(lon=60,lat=25), zoom=8,scale = "auto", maptype=c("satellite"),language = "EN")
lon=c(61.2554,61.1106,60.5507,60.3424,60.1677,59.5796,59.2854,59.0423)
lat=c(25.0381,25.0785,25.1210,25.1773,25.1905,25.2162,25.2694,25.2222)
geot=data.frame(lon,lat)
ggmap(map,extent="panel")+geom_point(aes(x=lon,y=lat,colour="red"),data=geot,cex=3)
could you please, inform me about the add order of phytoplankton density on station in fallow of these codes?
I have attached the excell sheet.
all the best
mahnaz
Hi Mahnaz,
One way to superimpose the value of density on the station is to read your spreadsheet as text, say variables (lon,lat,den), and then use:
for(k in 1:length(lon))
text(lon[k],lat[k],toString(den[k]))
The value of 'den' will be written in black on the location (lon[k],lat[k]), if you want to change to red use 'col=2'. If you want to format the value of density to look nice use:
toString(format(den[k],digits=8))
Hope this helps.
Regards,
Augusto
Dear Dr,Sanabria
thank you for your attention, I try to do it.
I send my request if i cannot.
all the best
mahnaz
@L. Augusto Sanabria
Dear Augusto
Thanks for your help.
How we can do spatial analysis with R?
I mean that we plot the map. then how we can do spatial analysis based on density data?
Each point has a density value and must be showed according density level. How we can preform it in R and on the plotted map?
Regards
Mohammad
Hi Mohammad,
If I understand you correctly what you want is to plot a given level of density on a map, that is, you have in some file in text form a 3D vector (lon, lat, den) where den is the density corresponding to point (lon,lat). Furthermore you want to plot a range of 10 levels of density in colors from blue to green to red (in my example the map is the State of Tasmania in Australia).
You can use the following piece of R code to do that (the plotting function is called
filled.contour())
x
Dear Augusto
Thanks a lot for your comment
I had a problem in running the filled.contour()) R code.
When I tried to run this piece of R code :
filled.contour(x,y,z,xlim=range(x,finite=T),ylim=range(y,finite=T),
zlim=c(min(z),max(z)) ,
nlevels=10,col=blue2green2red(10),
plot.title=title(main= tit1),
ylab="gust wind speed (m/s)",
plot.axes=FALSE,
key.title =title(main= "m/s") )
I faced with this error:
Error in min(z) : invalid 'type' (list) of argument
In fact, my z data frame is this:
> z
[,1]
[1,] Numeric,8
Is it correct? the matrix contains character vector?
Regards
Mohammad
Hi Mohammad,
How did you read the 3D vector of plain text (lon,lat,den)?
It looks like your 'z' column is a dataframe, you may need to extract in numerical form the column corresponding to den.
Regards,
Augusto
I used Mahnaz's data. I read it by read.xlsx code (package "xlsx")
I used this code:
den=read.xlsx(file="E:R/den.xlsx",1,header=T)
Should I change "header=T" to "header=F"?
Regards
Mohammad
Hi Mohammad,
Send the command 'head(den)' to see if you are reading the data correctly.
You should be able to extract the column corresponding to density, something like:
density
- Badges
- Science topic
- Similar topics
- Mathematics
- Statistics
- Statistical Software
- R Statistical Package