Versions Compared

Old Version 14

changes.mady.by.user Sylvie Lamy-Thepaut

Saved on

compared with

New Version 15

changes.mady.by.user Sylvie Lamy-Thepaut

Saved on

Key

  • This line was added.
  • This line was removed.
  • Formatting was changed.

...

Section


Column
width60%


Panel

mnetcdf (python) pnetcdf(fortran)

Magics++ is capable of reading NetCDF data files.

A family of netcdf parameters enable the user to define how to interpret the netcdf.


Panel
titleNew in 3.0.0

From this version, Magics will offer a easier setting of the NetCDF object.

The principle is to make it aware of some commonly used conventions of NetCDF representations. For example It will try to identify the latitudes and longitudes axis to set-up the geo-referencement.

This is work in progress, and we plan to introduce more of these convention conventions in the next releases.


Example of metadata (ncdump):

Code Block
titlencdump
collapsetrue
//Variables		
	   float longitude(longitude) ;
                longitude:units = "degrees_east" ;
                longitude:long_name = "longitude" ;
        float latitude(latitude) ;
                latitude:units = "degrees_north" ;
                latitude:long_name = "latitude" ;
        int time(time) ;
                time:units = "hours since 1900-01-01 00:00:0.0" ;
                time:long_name = "time" ;
                time:calendar = "gregorian" ;
        short t2a(time, latitude, longitude) ;
                t2a:scale_factor = 0.000146876453558398 ;
                t2a:add_offset = 0.988291258275906 ;
                t2a:_FillValue = -32767s ;
                t2a:missing_value = -32767s ;
                t2a:units = "K" ;
                t2a:long_name = "2 metre temperature anomaly" ;

Example of Magics code : no need to specify that the data are geo-referenced nor to explicitly define the latitude and longitude variable names:

Code Block
languagepy
titleNetcdf Setting
collapsetrue
data = mnetcdf(
               netcdf_filename ='netcdffile.nc'
               netcdf_time_dimension_setting = "2017-10-02 00:00:00", #extract the specified time 
               netcdf_value_variable = var
              )

anomaly = mcont(contour = "off",
                     legend = "on",
                     contour_shade = "on",
                     contour_level_selection_type = "level_list",
                     contour_level_list = [-15.00, -0.5, 0.5, 15.00],
                     contour_label = "off",
                     contour_label_height = 0.40,
                     contour_label_colour = "charcoal",
                     contour_label_frequency = 1,
                     contour_shade_method = "area_fill",
                     contour_shade_colour_method = "gradients",
                     contour_gradients_colour_list = ['blue','white','white', 'red'],
                     contour_gradients_step_list = [50, 1, 50]
                     )

plot(data, contour)


Panel
titleIntroduced in 2.31.0

From this version, Magics can understand data represented in a projection different than the traditional latlon.The NetCDF header should just contain the proj4 string representing the projection used to describe the data. This is still a very early stage, but contact us if you are interested in such a functionality.


Example of metadata (ncdump):

Code Block
titlencdump
collapsetrue
//Variables		
	   double x(x) ;
                x:standard_name = "projection_x_coordinate" ;
                x:long_name = "x coordinate of projection" ;
                x:units = "m" ;
        double y(y) ;
                y:standard_name = "projection_y_coordinate" ;
                y:long_name = "y coordinate of projection" ;
                y:units = "m" ;
	    float accumulation(duration, y, x) ;
                accumulation:long_name = "observed 24-hour rainfall accumulation" ;
                accumulation:_fillvalue = -9999.f ;
                accumulation:units = "mm" ;
                accumulation:grid_mapping = "lambert_azimuthal_equal_area" ;
// global attributes:
                :datatype = "operaGrid" ;
                :time = "09/01/2017 12:00:00" ;
                :conventions = "CF-1.5" ;
                :projection = "+proj=laea +lat_0=55.0 +lon_0=10.0 +x_0=1950000.0 +y_0=-2100000.0 +units=m +ellps=WGS84" ;
                :grid_corners = -10.4345768386404, 31.7462153193251, -39.5357864125034, 67.0228327583087, 57.8119647501499, 
								67.6210371027505, 29.421038635578, 31.987650277945 ;




Column
width30%


Panel
titleQuick links :

Gallery:

 

 



...