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NOTICE: This version of the NSF Unidata web site (archive.unidata.ucar.edu) is no longer being updated.
Current content can be found at unidata.ucar.edu.
To learn about what's going on, see About the Archive Site.
Gabor Fichtinger writes:
> I am asking if there is any existing (hopefully publicly
> available) point and click software handling NetCDF files?
> I'am thinking of a program that: (1) obtains descriptive info
> from NetCDF files, such as the number, name, dimension,
> dimension-name of variables, scale values; (2) could perform
> various netcdf operations on variables and complete NetCDF
> files (hyperslabs, sampling, catenations, etc...). All
> everything in a point'an click manner, perhaps based on
> X-Window. How about this?
I'm on a team developing software called Envision, which addresses
these areas. It runs on Unix workstations using X/Motif. A beta
version of the software will be freely available by anonymous FTP
beginning next month. I'm attaching a summary of the project below
and there are other documents about Envision available by anonymous
FTP from vista.atmos.uiuc.edu in pub/docs. We'll also make an
announcement to the netcdfgroup when the software is ready for beta
distribution. Thanks.
Keith
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Keith Searight, Research Programmer keith@xxxxxxxxxxxxxxxxxxxx
Univ. of Illinois, Atmospheric Sciences Ph. (217) 333-8132
105 S. Gregory Ave., Urbana, IL 61801 Fax (217) 244-4393
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ENVISION: A COLLABORATIVE ANALYSIS AND DISPLAY SYSTEM FOR LARGE
GEOPHYSICAL DATA SETS
Envision is a software project funded by NASA's Applied
Information Systems Research Project. It is a data management,
manipulation, and visualization package under joint development at the
University of Illinois Atmospheric Sciences Department and the Texas
A&M Meteorology Department.
It's purpose is to give researchers in the geophysical sciences
convenient ways to manage, browse, manipulate, and display large data
sets. It is being developed for Unix workstations using the C
language and has an X/Motif user interface. Data files using the
netCDF API are supported, with support for HDF planned for the near
future.
Envision's key features are:
(1) Organization of data sets by project. Data sets are grouped
together into a "project." Variables and dimensions that span
multiple files can be associated together into "logical" objects.
Once defined, logical objects can be used as if they were in a single
file. "Virtual" dimensions may also be defined in a project. These
are dimensions that are implied by the segmentation of data into
files, such as when each file represents a time step in a series of
measurements. New data files may be created from virtual dimensions
and logical objects. The advantage of this approach is that users can
concentrate more on their data and less on how it is stored.
(2) Metadata browsing and editing. Metadata is descriptive
information about dimensions and variables, such as their names,
units, valid ranges, fill values, instruments used, etc. Envision's
GUI provides convenient ways to browse this information and to alter
or add to it, enhancing the data's usefulness. These changes are
saved in an external project file, which avoids the need to recopy the
original files. The metadata can be written back to the original data
files if desired, as long as the user has write permission. With
media such as CD-ROMS, this capability would be extremely useful.
(3) Visualization. Envision displays data through several means.
The public domain NCSA tools XImage and Collage are used as viewers
for data values selected with Envision. Displays may be sourced from
multiple files, with the Envision data manager assembling the data on
the fly for transmission to the viewers. The data is sent using
NCSA's DTM, which is a public domain socket-based protocol. The
commercial visualization product IDL has also been linked with the
Envision data server to provide other types of visualization. These
tools will provide users with easy to use methods to quickly evaluate
a data set.
(4) Collaborative features. Envision is a collaborative package,
meaning that multiple users may interact with the same session. Users
on different machines may connect to the same Envision data server and
see the same X displays. Using Collage, which is also collaborative,
users may view the same visualization displays simultaneously. This
approach permits researchers at different sites to work together at
the same time and also facilitates remote demos of data visualization.
Envision is nearing its first beta release, planned for April,
1993. It will be made available at no charge by anonymous FTP to the
scientific community. It is being developed on IBM RS6000s and is
being ported to other Unix machines, including Sun, HP, SGI, and DEC.
Future plans for Envision include more support for data manipulation
and visualization. We encourage people to try out the software and
suggest changes and additions they'd like to see. We expect Envision
to be helpful to geophysical researchers and are excited about it's
future.
For more information, contact Keith Searight (keith@xxxxxxxxxxxxxxxxxxxx).
(revised 3/93)
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