[R-sig-Geo] Plotting x and y values using data from two separate netCDF files in R
Michael Sumner
md@umner @end|ng |rom gm@||@com
Tue Mar 26 21:33:54 CET 2019
I would try for a single point:
x <- raster::brick(ncfname, varname = "cum_co2_emi-CanESM2")
y <- raster::brick(ncfname1, varname = "onedaymax")
pt <- cbind(30, -5)
to_plot <- cbind(raster::extract(x, pt), raster::extract(y, pt))
plot(to_plot)
Is that close? You might be better off using raster::as.data.frame(x, xy =
TRUE, long = TRUE) if you want all locations at their actual centre.
See if the times of the 3rd axis are valid (and the same) in getZ(x) and
getZ(y).
There's rarely a need to use ncdf4 directly, though that's important
sometimes, more so for grids that raster's regular-affine referencing model
doesn't support.
cheers, Mike
On Wed, 27 Mar 2019 at 05:29 rain1290--- via R-sig-Geo <
r-sig-geo using r-project.org> wrote:
> Hi there,
> I am currently trying to plot precipitation data (y-axis values) with
> cumulative emissions data (x-axis) using R. Both of these data are found on
> two separate netCDF files that I have already read into R. Ultimately, What
> I would like to do is plot precipitation as a function of cumulative
> emissions for a selected location (as shown below in the following code). I
> have, so far, used the following code (with "#" to highlight each step):
> library(raster)
> library(ncdf4)
> library(maps)
> library(maptools)
> library(rasterVis)
> library(ggplot2)
> library(rgdal)
> library(sp) #Geting cumulative emissions data for x-axis
> ncfname<-"cumulative_emissions_1pctCO2.nc"
> Model1<-nc_open(ncfname)
> print(Model1)
> get<-ncvar_get(Model1, "cum_co2_emi-CanESM2") #units of terratones
> of
> carbon (TtC) for x-axis (140 values)
> print(get)
> Year<-ncvar_get(Model1, "time") #140 years
> #Getting Model data for extreme precipitation (units of millimeters/day)
> for y-axis ncfname1<-"MaxPrecCCCMACanESM21pctCO2.nc"
> Model2<-nc_open(ncfname1)
> print(Model2)
> get1<-ncvar_get(Model2, "onedaymax") #units of millimeters/day
> print(get1)
> #Reading in latitude, longitude and time from this file:
> latitude<-ncvar_get(Model2, "lat") #64 degrees latitude
> longitude<-ncvar_get(Model2, "lon") #128 degrees longitude
> Year1<-ncvar_get(Model2, "Year") #140 years
> #Plotting attempt randompointlon<-30 #selecting a longitude
> randompointlat<--5 #selecting a latitude
> Hope<-extract(r_brick,
> SpatialPoints(cbind(randompointlon,randompointlat)),method='simple')
> df<-data.frame(cumulativeemissions=seq(from=1, to=140, by=1),
> Precipitation=t(Hope))
> ggplot(data=df, aes(x=get, y=Precipitation,
> group=1))+geom_line()+ggtitle("One-day maximum precipitation
> (mm/day)
> for random location for CanESM2 1pctCO2 as a function of cumulative
> emissions")
> print(Model1) yields the following (I read in variable #2 for now):
> File cumulative_emissions_1pctCO2.nc (NC_FORMAT_NETCDF4):
> 14 variables (excluding dimension variables):
> float cum_co2_emi-BNU-ESM[time] (Contiguous storage)
> long_name: Cumulative carbon emissions for BNU-ESM
> units: Tt C
> float cum_co2_emi-CanESM2[time] (Contiguous storage)
> long_name: Cumulative carbon emissions for CanESM2
> units: Tt C
> float cum_co2_emi-CESM1-BGC[time] (Contiguous storage)
> long_name: Cumulative carbon emissions for CESM1-BGC
> units: Tt C
> float cum_co2_emi-HadGEM2-ES[time] (Contiguous storage)
> long_name: Cumulative carbon emissions for HadGEM2-ES
> units: Tt C
> float cum_co2_emi-inmcm4[time] (Contiguous storage)
> long_name: Cumulative carbon emissions for inmcm4
> units: Tt C
> float cum_co2_emi-IPSL-CM5A-LR[time] (Contiguous storage)
> long_name: Cumulative carbon emissions for IPSL-CM5A-LR
> units: Tt C
> float cum_co2_emi-IPSL-CM5A-MR[time] (Contiguous storage)
> long_name: Cumulative carbon emissions for IPSL-CM5A-MR
> units: Tt C
> float cum_co2_emi-IPSL-CM5B-LR[time] (Contiguous storage)
> long_name: Cumulative carbon emissions for IPSL-CM5B-LR
> units: Tt C
> float cum_co2_emi-MIROC-ESM[time] (Contiguous storage)
> long_name: Cumulative carbon emissions for MIROC-ESM
> units: Tt C
> float cum_co2_emi-MPI-ESM-LR[time] (Contiguous storage)
> long_name: Cumulative carbon emissions for MPI-ESM-LR
> units: Tt C
> float cum_co2_emi-MPI-ESM-MR[time] (Contiguous storage)
> long_name: Cumulative carbon emissions for MPI-ESM-MR
> units: Tt C
> float cum_co2_emi-NorESM1-ME[time] (Contiguous storage)
> long_name: Cumulative carbon emissions for NorESM1-ME
> units: Tt C
> float cum_co2_emi-GFDL-ESM2G[time] (Contiguous storage)
> long_name: Cumulative carbon emissions for GFDL-ESM2G
> units: Tt C
> float cum_co2_emi-GFDL-ESM2M[time] (Contiguous storage)
> long_name: Cumulative carbon emissions for GFDL-ESM2M
> units: Tt C 1 dimensions:
> time Size:140
> units: years since 0-1-1 0:0:0
> long_name: time
> standard_name: time
> calender: noleap 4 global attributes:
> description: Cumulative carbon emissions for the 1pctCO2 scenario
> from the CMIP5 dataset.
> history: Created Fri Jul 21 14:50:39 2017
> source: CMIP5 archieve
>
> print(Model2) yields the following:File MaxPrecCCCMACanESM21pctCO2.nc
> (NC_FORMAT_NETCDF4): 3 variables (excluding dimension variables):
> double onedaymax[lon,lat,time] (Contiguous storage)
> units: mm/day
> double fivedaymax[lon,lat,time] (Contiguous storage)
> units: mm/day
> short Year[time] (Contiguous storage) 3 dimensions:
> time Size:140
> lat Size:64
> units: degree North
> lon Size:128
> units: degree East 3 global attributes:
> description: Annual global maximum precipitation from the CanESM2
> 1pctCO2 scenario
> history: Created Mon Jun 4 11:24:02 2018
> contact: rain1290 using aim.com
> So, in general, this is what I am trying to achieve, but I am not sure if
> what I am doing in the ggplot function is the right approach for this.
> Any assistance with this would be greatly appreciated!
> Thanks,
> [[alternative HTML version deleted]]
>
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--
Dr. Michael Sumner
Software and Database Engineer
Australian Antarctic Division
203 Channel Highway
Kingston Tasmania 7050 Australia
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