MITgcm_contrib/netcdf_matlab_examples/README.txt


Examples:  NetCDF & MatLAB
==========================

These directories contain examples of MatLAB commands for reading,
creating, and modifying NetCDF files.  All the scripts use Chuck
Denham's MatLAB package which can be obtained at:

  "MexCDF and NetCDF Toolbox For Matlab-5&6"
  http://woodshole.er.usgs.gov/staffpages/cdenham/public_html/MexCDF/nc4ml5.html

and must first be installed.


The NetCDF files generated here are intended for use with Ingrid:

  http://ingrid.mit.edu/

As a result, they approximately follow the simple COARDS convention
which is described at:

  http://www.unidata.ucar.edu/packages/netcdf/conventions.html
  http://ferret.wrc.noaa.gov/noaa_coop/coop_cdf_profile.html


The key items for the use of NetCDF files within Ingrid are:

  1) In order to work with the Ingrid "plot land" option, dimensions
     should have units of "degree_east" and "degree_north" as, for
     example, specified by:

       nc{'lon'}.units = 'degree_east';
       nc{'lat'}.units = 'degree_north';

     The actual dimension names (eg. "lat" or "Y") are unimportant.

  2) It is generally a good idea to set the "gridtype" to 1 or 0 to
     indicate that the coordinate "wraps" or not.  The gridtype
     attribute allows Ingrid to, for instance, plot longitudinal data
     over "wrapped" ranges such as -100 to 500deg.  The attribute can
     be set using commands such as:

       nc{'X'}.gridtype = ncint(1);
       nc{'Y'}.gridtype = ncint(0);

  3) Ingrid does seem to correctly handle the "_FillValue" attribute
     and it can be set using a MatLAB command such as:

       nc{ idu }.FillValue_ = ncdouble(-9999.0);

     [ Note how the "_" character is moved to the end of the attribute
       name since MatLAB cannot correctly handle variable names with a
       leading underscore. ]
1	edhill	1.1
2			Examples: NetCDF & MatLAB
3			==========================
4
5			These directories contain examples of MatLAB commands for reading,
6			creating, and modifying NetCDF files. All the scripts use Chuck
7			Denham's MatLAB package which can be obtained at:
8
9			"MexCDF and NetCDF Toolbox For Matlab-5&6"
10			http://woodshole.er.usgs.gov/staffpages/cdenham/public_html/MexCDF/nc4ml5.html
11
12			and must first be installed.
13
14
15			The NetCDF files generated here are intended for use with Ingrid:
16
17			http://ingrid.mit.edu/
18
19			As a result, they approximately follow the simple COARDS convention
20			which is described at:
21
22			http://www.unidata.ucar.edu/packages/netcdf/conventions.html
23			http://ferret.wrc.noaa.gov/noaa_coop/coop_cdf_profile.html
24
25
26			The key items for the use of NetCDF files within Ingrid are:
27
28			1) In order to work with the Ingrid "plot land" option, dimensions
29			should have units of "degree_east" and "degree_north" as, for
30			example, specified by:
31
32			nc{'lon'}.units = 'degree_east';
33			nc{'lat'}.units = 'degree_north';
34
35			The actual dimension names (eg. "lat" or "Y") are unimportant.
36
37			2) It is generally a good idea to set the "gridtype" to 1 or 0 to
38			indicate that the coordinate "wraps" or not. The gridtype
39			attribute allows Ingrid to, for instance, plot longitudinal data
40			over "wrapped" ranges such as -100 to 500deg. The attribute can
41			be set using commands such as:
42
43			nc{'X'}.gridtype = ncint(1);
44			nc{'Y'}.gridtype = ncint(0);
45
46			3) Ingrid does seem to correctly handle the "_FillValue" attribute
47			and it can be set using a MatLAB command such as:
48
49			nc{ idu }.FillValue_ = ncdouble(-9999.0);
50
51			[ Note how the "_" character is moved to the end of the attribute
52			name since MatLAB cannot correctly handle variable names with a
53			leading underscore. ]