JHV User's Guide
Getting Started
This section gives an overview of the Java HDF Viewer (JHV), which includes loading an HDF file and choosing view options.
1. Get Started
After you install and start the JHV properly, the JHV window should popup and look like the following picture. This window is called the Java HDF Viewer (JHV). There are five basic components in the JHV, the menubar, tree canvas, image canvas, file field and text area. The menubar is used to load or close a file, choose view option and display JHV version information. The tree canvas is located at the top left of the JHV, and used to display the hierarchy tree of an HDF file. The image canvas is located the top right of the JHV and used to display preview image for the chosen HDF object. The file field is located in the middle for entering file names. The text area, located at the bottom, is used to display all text information such as file annotation, data attributes, error message, etc. The following is the JHV window.
2. Load File
There are two ways to load an HDF file, from file field and from file menu. After an HDF file is loaded, the hierarchy of the file shows on the tree canvas. The JHV currently only support HDF files. It does not read any other file format.
- Loading file from the file field gives direct access to the target file. You first type the file name in the file field, then either press the "Enter" key or click the "Load File" button located at the right of the file field. If the file entered is valid HDF file, the JHV will display the HDF hierarchy tree for the file. If the entered file is a path, the JHV opens the local file manager. You can choose a file to open from the file manager.
- Loading file form the file menu opens the local file manager with default file path. When you click the file menu and choose the "Open Local File" item or press CTRL+O. The JHV opens the local file manager with the default file path. The following is example of the local file manager from Windows 95.

3. Display Message
All text information is displayed in the text area. For example, if you click the file annotation in the hierarchy tree, the annotation shows in the text area. You can scroll up and down the text area to see the full text. The following is an example of displaying file annotation.

4. Set View option
JHV provides the capability to view HDF 8-bit raster images by animation or layers. The view menu in the menubar has three items, Default, Animation and Layer. When you click a folder (an HDF hierarchy node) which contains more than one 8-bit Raster Images, the folder expands by default, animation window pops up by the animation option or the layer window pops up by the layer option. More details can be found in sections Animation and Image Overlay.
5. Exit JHV
To exit JHV, click the file menu and choose exit, or press key "CTRL+E".

The National Center for Supercomputing Applications
University of Illinois at Urbana-Champaign
hdfhelp@ncsa.uiuc.edu