NCDF_BROWSER Name
NCDF_BROWSER Purpose
This program is designed to make it easier to browse and read the
data and metadata in netCDF and HDF files. The user can browse files,
and read the data and metadata into main-level IDL variables. New netCDF
and HDF files can be opened at any time. The user interacts with the
program via a browser window (GUI). This program is a wrapper for the
NCDF_DATA object (ncdf_data__define.pro), which must also be downloaded.
Note that only HDF files with scientific datasets (SD) can be read currently.
There is no support for VDATA objects or other objects sometimes found in HDF
files. Also note that when variables are returned from HDF files, they are returned
in a calibrated form, if calibration information about the variable is present in the
file. Calibration information is presented as an extra variable attribute in the
browser.
calibratedData = calData.cal * (uncalibratedData - calData.offset)
Author
FANNING SOFTWARE CONSULTING
David Fanning, Ph.D.
1645 Sheely Drive
Fort Collins, CO 80526 USA
Phone: 970-221-0438
E-mail: david@idlcoyote.com
Coyote's Guide to IDL Programming: http://www.idlcoyote.com
Category
File I/o
Calling Sequence
IDL> NCDF_Browser, filename Arguments
filename: The name of a netCDF and HDF file to open and browse.
Keyword Parameters
EXTENSION: In general, netCDF and HDF files use *.nc, *.ncf, *.ncdf and *.hdf file extensions to
identify themselves as netCDF and HDF files. Some users have their own file extensions.
You can use this keyword to identify the file extension you wish to use. If
set here, it will be used as the file filter in place of the normal file
extensions in DIALOG_PICKFILE.
obj = ('NCDF_DATA', file, EXTENSION='*.bin')
NO_NEW_FILE: If this keyword is set, then the button that allows a new file to be open
on the browser is not created.
NO_READ_ON_PARSE: Normally, when a file is opened it is parsed for information.
One piece of information is the minimum and maximum values of the variables.
This requires actually reading the variables. This can slow things down
considerably is the variable is large. Setting this keyword will suppress
the reading of the variables during the parsing of the data file, with the
result that no minimum or maximum values will be reported.
TITLE: Set this keyword to a string that is on the title bar of the browser.
XOFFSET: Set this keyword to the X offset in pixels of the top-left corner of the browser.
YOFFSET: Set this keyword to the Y offset in pixels of the top-left corner of the browser.
Notes
This program is only a (useful) front-end for a more flexible
object program of class NCDF_DATA. In this front end, the NCDF_DATA
object is created and then destroyed when the GUI is destroyed.
The NCDF_DATA object can be used to read netCDF data in a non-interactive
way, if you prefer not to use a GUI to interact with the data file.
REQUIRES:
The following programs are required from the Coyote Library.
http://www.idlcoyote.com/netcdf_data__define.pro
http://www.idlcoyote.com/error_message.pro
http://www.idlcoyote.com/centertlb.pro
http://www.idlcoyote.com/undefine.pro
http://www.idlcoyote.com/textbox.pro
http://www.idlcoyote.com/fsc_base_filename.pro
http://www.idlcoyote.com/textlineformat.pro
Modification History
Written by: David W. Fanning, 03 Feb 2008. Used ideas from many
people, including Chris Torrence, Ken Bowman, Liam Gumely,
Andrew Slater, and Paul van Delst.
Added Extension keyword. DWF. 04 Feb 2008.
Added error handling and protection for NCDF variables that have a dimension of length zero. 22 April 2009. DWF.
Added NO_READ_ON_PARSE keyword. 22 April 2009. DWF.
Now convert NCDF CHAR type variables to strings on output. 22 April 2009. DWF
Made the default value of NO_READ_ON_PARSE set to 1. 25 June 2009. DWF.
Added NO_NEW_FILE keyword to suppress the Open File button. 3 February 2010. DWF.
Added TITLE, XOFFSET, and YOFFSET keywords. 5 February 2010. DWF.
Fixed a problem with memory leakage when the input file cannot be read. 1 May 2010. DWF.