The document discusses view_hdf, a visualization and analysis tool developed to access data from HDF products generated by NASA's CERES Data Management System. view_hdf allows users to select and plot variables from CERES Science Data Sets without needing knowledge of HDF formats. It provides capabilities such as 2D and 3D graphics, geographic mapping, statistics computation, and saving/printing plots. Contact information is provided for accessing the CERES data center and documentation for view_hdf.

1. view_hdf
Kam-Pui Lee, SAIC
CERES Data Management Team
Linda Hunt, CSC
NASA Langley DAAC
HDF-EOS Workshop II
September 22, 1998

2. Introduction
* NASA Langley Research Center has developed the Clouds
and the Earth's Radiant Energy System (CERES) instrument
to study the Earth's climate and environment
* The CERES Data Management System has been
developed by the Atmospheric Sciences Division to generate
science data products from the instrument measurements
* This system is now operational at the Langley Distributed
Active Archive Center (DAAC) producing archival data sets
written in Hierarchical Data Format (HDF)

3. * A visualization and analysis tool (view_hdf) has been
written in Interactive Data Language (IDL) to access data
from HDF products
* This tool is developed on a UNIX platform with a
graphical user interface (GUI) to manipulate the data
* User does not need any knowledge of HDF
* view_hdf has been tested on Solaris, IRIX, HP-UX and
DEC Alpha operating systems

4. Capabilities of view_hdf
* Select and subset variables from either Science Data Sets
(SDS) or Vdata structures
* Render both two and three dimensional graphics
* Plot geolocated data onto various world map projections
* Plot multiple variables
* Plot difference of two variables
* Compute statistics
* Create subset of data based on the range of another
criterion variable
* Display data from the screen
* Save plot in Postscript or GIF format
* Send plot directly to a printer
* Export data to a file in ASCII format

5. User's Guide
* The URL for the draft User's Guide to view_hdf is: http://
asd-www.larc.nasa.gov/ceres/collect_guide/list.html
(will be relocated at the DAAC when final version is
available)
Contacts for Data Center/Data Access Information and view_hdf
program:
Langley DAAC User and Data Services Office
NASA Langley Research Center
Mail Stop 157D
2 South Wright Street
Hampton, VA 23681-2199
USA
Telephone: (757) 864-8656
FAX: (757) 864-8807
E-mail: larc@eos.nasa.gov
URL: http://eosweb.larc.nasa.gov

6. User's Guide
* The URL for the draft User's Guide to view_hdf is: http://
asd-www.larc.nasa.gov/ceres/collect_guide/list.html
(will be relocated at the DAAC when final version is
available)
Contacts for Data Center/Data Access Information and view_hdf
program:
Langley DAAC User and Data Services Office
NASA Langley Research Center
Mail Stop 157D
2 South Wright Street
Hampton, VA 23681-2199
USA
Telephone: (757) 864-8656
FAX: (757) 864-8807
E-mail: larc@eos.nasa.gov
URL: http://eosweb.larc.nasa.gov