HDF_BROWSER

The HDF_BROWSER function presents a graphical user interface (GUI) which allows the user to view the contents of an Hierarchical Data Format (HDF) file, and prepare a template for extraction of HDF data and metadata into IDL. The output template is an IDL structure that may be used when reading HDF files with the HDF_READ routine. If you have several HDF files of identical form, the returned template from HDF_BROWSER may be reused to extract data from these files with HDF_READ. If you do not need a multi-use template, you may call HDF_READ directly.

This routine is written in the IDL language. Its source code can be found in the file


hdf_browser.pro

in the

lib

subdirectory of the IDL distribution.

Keywords

CANCEL

Set this keyword to a named variable that will contain the byte value 1 (one) if the user clicked the "Cancel" button or the byte value 0 (zero) otherwise.

PREFIX

When HDF_BROWSER reviews the contents of an HDF file, it creates default output names for the various data elements. By default these default names begin with a prefix derived from the filename. Set this keyword to a string value to be used in place of the default prefix.

Graphical User Interface Menu Options

The following options are available from the graphical user interface menus.

Pulldown Menu

The following table shows the options available with the pulldown menu.

HDF_BROWSER Pulldown Menu Options
Menu Selection	Description
HDF Summary	Overview of HDF file contents
DFR8 (8-bit Images)	8-bit images, palettes, and their attributes
DFAN Elements	File annotations and descriptions
DF24 (24-bit Images)	24-bit images and their attributes
DFP (Palettes)	Image palettes
SD (Variables/Attributes)	Scientific Datasets and attributes

View Image Button

If you have selected an image from the pulldown menu, click on this button to view the image.

2-D Plot Button

If you have selected a data item that can be plotted in two dimensions, click on this button to view a 2D plot of the data.

Read Checkbox

Select this checkbox to extract the current data or metadata item from the HDF file.

Extract As

Specify a name for the extracted data or metadata item

NOTE: The Read Checkbox must be selected for the item to be extracted. Default names are generated for all data items, but may be changed at any time by the user.

Example

template = HDF_BROWSER('test.hdf')

output_structure = HDF_READ(TEMPLATE=template)

or,

output_structure = HDF_READ('test.hdf', TEMPLATE=template)

NOTE: Vgroups and Vdata's are not currently supported. HDF files written with HDF4.1 or greater may not be readable with this browser. Because of a bug in HDF4.0r2, multiple use of HDF_BROWSER on files containing both DFR8 and DF24 images may cause the DFR8 and DF24 interfaces to become unusable. In these cases, HDF_BROWSER will improperly indicate that there are no DFR8 or DF24 images in the HDF file, and all access to these interfaces will fail for the duration of the IDL session. Restarting IDL will allow you to again use HDF_BROWSER to view the full contents of the HDF file.