HDF_BROWSER

The HDF_BROWSER function presents a graphical user interface (GUI) that allows the user to view the contents of a Hierarchical Data Format (HDF), HDF-EOS, or NetCDF file, and prepare a template for the 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.

Graphical User Interface Menu Options

Pulldown Menu


Menu Selection	Description
HDF/NetCDF Summary
DF24 (24-bit Images)	24-bit images and their attributes
DFR8 (8-bit Images)	8-bit images and their attributes
DFP (Palettes)	Image palettes
SD (Variables/Attributes)	Scientific Datasets and attributes
AN (Annotations)	Annotations
GR (Generic Raster)	Images
GR Global (File) Attributes	Image attributes
VGroups	Generic data groups
VData	Generic data and attributes
HDF-EOS Summary
Point	EOS point data and attributes
Swath	EOS swath data and attributes
Grid	EOS grid data and attributes

Preview Button

If you have selected an image, 2D data set, or 3xnxm data set from the pulldown menu, click on this button to view the image. 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 (the default) or click on the "Surface" radio button to display a surface plot, click on the "Contour" radio button to display a contour plot, or click on the "Show3" radio button for an image, surface, and contour display. You can also select the "Fit to Window" checkbox to fit the image to the window.

Read Checkbox

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

Extract As

Syntax

Template = HDF_BROWSER([Filename] [, CANCEL=variable] [, GROUP=widget_id] [, PREFIX=string])

Return Value

Returns a template structure containing heap variable references, or 0 if no file was selected. The user is required to clean up the heap variable references when done with them.

Arguments

Filename

A string containing the name of an HDF file to browse. If Filename is not specified, a dialog allows you to choose a file.

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.

GROUP

Set this keyword to the widget ID of a widget that calls HDF_BROWSER. When this ID is specified, a death of the caller results in the death of the HDF_BROWSER. The following example demonstrates how to use the GROUP keyword to properly call HDF_BROWSER from within a widget application. To run this example, save the following code as browser_example.pro:

PRO BROWSER_EXAMPLE_EVENT,ev 
 
   WIDGET_CONTROL,ev.id,GET_VALUE=val 
      CASE val of 
         'Browser':BEGIN 
            a=HDF_BROWSER(GROUP=ev.top) 
            HELP,a,/st 
         END 
         'Exit': WIDGET_CONTROL,ev.top,/DESTROY 
      ENDCASE 
 
END 
 
PRO BROWSER_EXAMPLE 
 
   a=WIDGET_BASE(/ROW) 
   b=WIDGET_BUTTON(a,VALUE='Browser') 
   c=WIDGET_BUTTON(a,VALUE='Exit') 
   WIDGET_CONTROL,a,/REALIZE 
   XMANAGER,'browser_example',a 
 
END

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.

Examples

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

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