1. view_hdf Kam-Pui Lee Science Applications International Corporation CERES Data Management Team Linda Hunt Computer Sciences Corporation Atmospheric Sciences Data Center NASA Langley Research Center Atmospheric Sciences Data Center NASA LaRC

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 to generate science data products from the instrument measurements This system is now operational at the Atmospheric Sciences Data Center (DAAC) producing archival data sets written in Hierarchical Data Format (HDF) A visualization and analysis tool, view_hdf, has been written in Research Systems’ Interactive Data Language (IDL) to access data from HDF products Atmospheric Sciences Data Center NASA LaRC

3. view_hdf overview Consists of IDL routines and a C shared library, with a graphical user interface (GUI) to manipulate the data Developed on a Unix platform; built and tested on Solaris, Irix, HP-UX, and DEC/Compaq Alpha operating systems Currently being tested on PC platforms An IDL-only version is under development that eliminates the C shared library, making view_hdf portable to any system which can run IDL Developed for the CERES project but useful with other data sets written in HDF and HDF-EOS Atmospheric Sciences Data Center NASA LaRC

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 Perform simple arithmetic operations on two variables Compute statistics Create subsets of data based on the value of another criterion variable Perform curve fitting and regression Create histograms Atmospheric Sciences Data Center NASA LaRC

5. Capabilites of view_hdf Display data values to the screen Export data to a file in ASCII or HDF formats Save plots in PostScript or GIF format Send plots directly to a printer Execute a user-defined IDL procedure Atmospheric Sciences Data Center NASA LaRC

6. Obtaining view_hdf view_hdf is distributed by the Atmospheric Sciences Data Center at NASA Langley: http://eosweb.larc.nasa.gov support is available from Science, User and Data Services Atmospheric Sciences Data Center NASA Langley Research Center MS 157 D, 2 S. Wright St. Hampton, VA 23681-2199 USA e-mail: larc@eos.nasa.gov Phone: 757-864-8656Fax: 757-864-8807 Atmospheric Sciences Data Center NASA LaRC

7. Main Menu

8. Open with vgroup

9. List SDS and vdata Names

10. Range Input Window

11. Import Data

12. Select Function Menu

13. Geolocated Plot

14. Daytime Total Filtered Radiance

15. Show Subset Range

16. Histogram of Scene ID

17. Multivariable Plot

18. Grid Contour Plot

19. Curve Fit