Since HDF files are self-describing, it is possible to write standard browser utilities to scan the contents, display the results and, in some cases, plot the stored data. Any utility written to access HDF files can also be used to access NeXus files. However, NeXus makes extensive use of Vgroup classes in order to make the structure of the files more transparent, and so browsers are being developed to take advantage of this.
As the NeXus project develops, we anticipate more general purpose utilities and applications becoming available. In fact, this is one of the main objectives in developing the NeXus standard. Since the project is still in the early stages of development, this page is only gradually filling up. We encourage the neutron and X-ray scattering communities to contact me and help fill it up. Note that I have not tested all the products listed here, so the following references do not imply a personal endorsement.
Although it is possible to use standard HDF browsers to inspect the contents of NeXus files, there are some advantages to using NeXus-specific ones. At present, the only one available is a simple terminal browser with a command-line interface, although others are under development. HDF browsers are available for a variety of platforms, and include Java web-browser plug-ins. Look at the HDF web pages for further details.
NXbrowse <file_name>If no file name is given, the user is prompted for the file to be opened. NXbrowse then lists the global attributes and prompts for further commands. The following commands may be given in upper or lower case (although the group and data names are case sensitive) :
| Command | Definition |
|---|---|
| DIR | List the contents of the currently open group. |
| OPEN <group_name> | Open the specified group. |
| READ <data_name[i,j,...]> | Read the contents of the specified data set. If no array indices are specified, the first three elements of the data set are output along with all its attributes. If an array index is specified, only that element is output. Note that the order of the array indices follows the C-convention (the last index is the most-rapidly varying). |
| DUMP <data_name> <file_name> | Write the entire contents of the specified data set to the specified ASCII file. |
| BYTEASCHAR | Toggle the output format for NX_INT8 and NX_UINT8 variables. By default, they are output as integers, but after giving this command, they are printed as character strings. |
| CLOSE | Close the currently open group. At the root level of the NeXus file, this command is ignored. |
| EXIT, QUIT | Exit the program. |
| HELP | List the available commands. |
NXtoXML <NeXus_file> <XML_file>On most systems, NXtoXML is compiled and linked during the standard NeXus installation (v2.0 and later). Precompiled binary versions are available for a limited number of operating systems (Linux, VMS, Macintosh). Please contact Ray Osborn for more information.
NXtoDTD <NeXus_file> <XML_file>On most systems, NXtoDTD is compiled and linked during the standard NeXus installation (v2.0 and later). Precompiled binary versions are available for a limited number of operating systems (Linux, VMS, Macintosh). Please contact Ray Osborn for more information.
NXtree [-[no]attr] [-[no]data] [-html | -latex] <NeXus_file>The file NXtree.tar.gz contains the source code to be used on u**x platforms and NXtree-win32.zip contains a binary version for various flavors of Windows. It was written by Thomas Proffen <tproffen@lanl.gov>
Any visualization software that can read HDF files, such as IDL and Noesys, will be able to read NeXus files. However, a number of neutron and X-ray specific applications will soon be able to read NeXus files.
This section will probably take the longest to fill up although I am aware of a number of people responsible for analysis packages who intend to support NeXus when it is more developed.
Comments to: Ray Osborn <ROsborn@anl.gov>
Revised: Saturday, September 14, 2002
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