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Great work is and has been done for GDL! A question arises for me: are there plans to fully support netCDF4? Maybe in the near future?
The answer is yes (i.e. a patch to support it would be very welcome).
The plotting issues and documentation have higher priority now, in my opinion, though.
Does current IDL release support netCDF4-specific API calls?
Great! I run IDL8.1 now for three days - writing routines for reading our netCDF4 files. It seems that IDL8.1 mostly supports netCDF4 features like additional types of variables and so on. Regarding the support of user defined compound data I am not sure. I failed to read such data strutures. Also a routine for defining a compound data type I could not find until now. netCDF4 is quite nice, combining netCDF and HDF.
At least for me it would be great to have GDL als well! I will check some IDL routines from the experimental lab if they are running under GDL or not.
Thanks. It would certainly help if you could provide us with a list of examples showing what works and what does not work with netcdf4 in GDL.
thanks for your effort!
For creating a netCDF-4file I used the examples provided by unidata:
and here looking at the section: NetCDF-4 Examples - simple_nc4
where we may find * simple_nc4_wr.c and * simple_nc4_rd.c for writing and reading the file simple_nc4.nc
Here is now what I get in GDL:
GDL - GNU Data Language, Version 0.9.1
- For basic information type HELP,/INFO
- Default library routine search path used (GDL_PATH/IDL_PATH env. var. not set):
- No startup file read (GDL_STARTUP/IDL_STARTUP env. var. not set).
- Please report bugs, feature or help requests and patches at:
GDL> file_name = 'simple_nc4.nc' ;Default input file name
GDL> id = NCDF_OPEN(file_name) ;Open netCDF input file
GDL> grpids = NCDF_GROUPSINQ(id)
% Function not found: NCDF_GROUPSINQ
% Execution halted at: $MAIN$
OK, it's clear because we need netCDF-4 support.
In IDL8.1 I can go further on with reading the netCDF-4 file. The following lines work fine in IDL8.1:
file_name = 'simple_nc4.nc' ;Default input file name
id = NCDF_OPEN(file_name) ;Open netCDF input file
grpids = NCDF_GROUPSINQ(id)
grp1id = grpids
grp2id = grpids
grp1name = NCDF_GROUPNAME(grp1id)
grp2name = NCDF_GROUPNAME(grp2id)
DimIds = NCDF_DIMIDSINQ(id)
NCDF_DIMINQ, id, DimIds, x, dimSizex
NCDF_DIMINQ, id, DimIds, y, dimSizey
varid1 = NCDF_VARID(grp1id, 'data')
INQ_VID1 = NCDF_VARINQ(grp1id,varid1)
NCDF_VARGET, grp1id, varid1, data1 ;Read variable 'data'
Troubles start in IDL8.1 when I try to process the compound data in the group grp2 using lines like this:
varid2 = NCDF_VARID(grp2id, 'data')
INQ_VID2 = NCDF_VARINQ(grp2id,varid2)
NCDF_VARGET, grp2id, varid2, data2 ;Read variable 'data'
In my case, the netCDF-4 file looks in principle similar to that from the example mentioned above.
I will try to check reading of classical netCDF files with GDL using the examples (data files and IDL examples) provided by unidata.
Thank you very much!
I did some checks of netCDF (pre netCDF-4) functionality in GDL using the IDL code examples provided by unidata
These examples work well.
As expected, just creating a netCDF-4 file fails in GDL:
GDL> id = NCDF_CREATE('tt.nc', /NETCDF4_FORMAT, /CLOBBER)
% NCDF_CREATE: Keyword parameter NETCDF4_FORMAT not allowed in call to: NCDF_CREATE
% Execution halted at: $MAIN$