about netcdf files

On Aug 1, 2016, at 10:35 AM, lily li <chocold12 at gmail.com> wrote:

Hi all,

I can read the data, but how to plot it using ggplot or something? In this
case, x-axis should be longitude, and y-axis should be latitude. I tried to
plot using raster function, but the x and y axes are from 0 to 1.
Thanks again.

The code is like this:
pre1 = nc_open('sample_precip_daily.nc')
pre.3d = ncvar_get(pre1, 'precipitation')

require(raster)
rplot = t(pre.3d[, , 1])
r = raster(rplot[nrow(rplot):1, ]
plot(r)


On Tue, Jul 26, 2016 at 1:07 PM, lily li <chocold12 at gmail.com> wrote:

Thanks for your reply. But it says "Error in (function (classes, fdef,
mtable)):
unable to find an inherited method for function 'brick' for signature
'ncdf4' "

The dataset is attached. It contains daily precipitation data for 20
years, within a rectangle, so that there are several grid points. I use the
code to open it, but don't know how to get csv files, while each file
contains continuous daily precipitation data for each grid cell.
pre1 = nc_open('sample_precip_daily.nc')
pre1
pre1_rd = ncvar_get(pre1, 'precipitation')
nc_close(pre1)

Thanks for your help.

On Tue, Jul 26, 2016 at 4:08 AM, Jon Skoien <jon.skoien at jrc.ec.europa.eu>
wrote:

You could try with the brick function from the raster package.

bvar = brick(netcdfName)

This uses the ncdf4 functions for opening and reading the netcdf, but
makes it easier to extract data for each day:

p1 = rasterToPoints(bvar[[1]])
and write p1 to csv.

Best,
Jon



On 7/26/2016 6:54 AM, lily li wrote:

Hi all,

I have a problem in opening netcdf files. If one netcdf file contains
longitude, latitude, and daily precipitation. How to relate each
precipitation record to its associated location, and export them as csv
files? Thanks.

I just use nc_open(), ncvar_get(), but it is not very helpful. Thanks for
any ideas.

       [[alternative HTML version deleted]]

--
Jon Olav Sk?ien
Joint Research Centre - European Commission
Institute for Space, Security & Migration
Disaster Risk Management Unit

Via E. Fermi 2749, TP 122,  I-21027 Ispra (VA), ITALY

jon.skoien at jrc.ec.europa.eu
Tel:  +39 0332 789205

Disclaimer: Views expressed in this email are those of the individual and
do not necessarily represent official views of the European Commission.

	[[alternative HTML version deleted]]

Hi Lily:

If you download the vignette to my xtractomatic package  (
http://coastwatch.pfeg.noaa.gov/xtracto/index.html) there are any number
of examples using ggplot2 to make maps from netcdf data,

HTH,

-Roy

On Aug 1, 2016, at 10:35 AM, lily li <chocold12 at gmail.com> wrote:

Hi all,

I can read the data, but how to plot it using ggplot or something? In

this

case, x-axis should be longitude, and y-axis should be latitude. I tried

to

plot using raster function, but the x and y axes are from 0 to 1.
Thanks again.

The code is like this:
pre1 = nc_open('sample_precip_daily.nc')
pre.3d = ncvar_get(pre1, 'precipitation')

require(raster)
rplot = t(pre.3d[, , 1])
r = raster(rplot[nrow(rplot):1, ]
plot(r)


On Tue, Jul 26, 2016 at 1:07 PM, lily li <chocold12 at gmail.com> wrote:

Thanks for your reply. But it says "Error in (function (classes, fdef,
mtable)):
unable to find an inherited method for function 'brick' for signature
'ncdf4' "

The dataset is attached. It contains daily precipitation data for 20
years, within a rectangle, so that there are several grid points. I use

the

code to open it, but don't know how to get csv files, while each file
contains continuous daily precipitation data for each grid cell.
pre1 = nc_open('sample_precip_daily.nc')
pre1
pre1_rd = ncvar_get(pre1, 'precipitation')
nc_close(pre1)

Thanks for your help.

On Tue, Jul 26, 2016 at 4:08 AM, Jon Skoien <

jon.skoien at jrc.ec.europa.eu>

wrote:

You could try with the brick function from the raster package.

bvar = brick(netcdfName)

This uses the ncdf4 functions for opening and reading the netcdf, but
makes it easier to extract data for each day:

p1 = rasterToPoints(bvar[[1]])
and write p1 to csv.

Best,
Jon



On 7/26/2016 6:54 AM, lily li wrote:

Hi all,

I have a problem in opening netcdf files. If one netcdf file contains
longitude, latitude, and daily precipitation. How to relate each
precipitation record to its associated location, and export them as

csv

files? Thanks.

I just use nc_open(), ncvar_get(), but it is not very helpful. Thanks

for

any ideas.

       [[alternative HTML version deleted]]

--
Jon Olav Sk?ien
Joint Research Centre - European Commission
Institute for Space, Security & Migration
Disaster Risk Management Unit

Via E. Fermi 2749, TP 122,  I-21027 Ispra (VA), ITALY

jon.skoien at jrc.ec.europa.eu
Tel:  +39 0332 789205

Disclaimer: Views expressed in this email are those of the individual

and

do not necessarily represent official views of the European Commission.

      [[alternative HTML version deleted]]