Source: http://hdfeos.org/workshops/ws04/presentations/Khalsa/Khalsa_PHDIS.ppt

1. The Polar HDF-EOS Data Imaging
and Subsetting (PHDIS) Tool
Siri Jodha Singh Khalsa
Emergent Information Technologies, Inc.
National Snow and Ice Data Center,
University of Colorado
khalsa@colorado.edu
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2. Genesis – ESDIS Prototype



HDF_EOS IV
Evaluate suitability of HDF-EOS for
data sets in polar projections
Convert sample NSIDC DAAC data
sets to HDF-EOS
Build tools to subset, subsample,
visualize and export data fields from
multiple products
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3. Realize the promise of HDFEOS



HDF_EOS IV
One tool to open, read, display and
subset any data set
Utilize geolocation metadata
Provide simple interface for
geographic subsetting, subsampling,
and export
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4. DAAC Perspective

Be able to provide a single tool for all
polar gridded DAAC data sets
•
•
HDF_EOS IV
Heritage: AVHRR, SSM/I, TOVS
Future: MODIS, AMSR, GLAS
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5. Demonstration

The Polar HDF-EOS Data Imaging
and Subsetting Tool
•

For any HDF-EOS file a user can:
•
•
•
•
HDF_EOS IV
IDL-based (multi-platform)
examine data contents
visualize and compare the data fields
overlay lat/lon lines and/or coastlines
designate subregions for zooming in
on or displaying values
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6. Opening Window



Select one or more file to examine
When one or more files have been selected the
Load Data Field(s) window is opened.
When data fields have been loaded, user returns
to this screen to View Image Data

7. Selecting Data to Load


Available fields
from all selected
files are displayed
along with
projection
information.
Clicking on a field
name loads it.

8. Displaying a Data Field



Selected fields are grouped by projection.
Clicking on a row will open a window containing
the first field in that projection.
User may replicate the window or toggle through
the images in the default window

9. Initial Display


Data displayed with
gray scale palette.
Mode menu changes
click action
•
•
•
Toggle images
Define zoom box
Browse: select
between multiple
zoom boxes.

10. User first selects
one or more files
to open.
Metadata is read and
displayed. User then
selects field(s) to load.
Table of values includes
location and size of selected
region.
Double clicking in a box
brings up this menu.
(Print and Write to File
Selecting “View
will be added.)
Image Data” brings
up window from
which user selects
field to visualize.
Top level window is scaled to fit
user’s display while showing
entire data array. User can load
multiple fields and toggle
Instructions for defining
between them or display them a
in newregion of interest (ROI) in
windows.
any visualization window.
Box parameters displayed
while user positions box.
Multiple ROI boxes can be
registered. Contents
visualized in new window and
can be displayed in a table.

11. Image with Legend

Includes palette and a thumbnail image
locating the current window in overall
array if zoomed.

12. New Features to be Added






HDF_EOS IV
Coupled images from different grids.
Coastline and graticule overlay in
zoom window.
Autoreplicate for 3 or less fields.
View Core and Structural metadata.
Mapping between table cell and
image pixel
Read and display swath data.
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13. Conclusions


HDF-EOS enables discipline-specific
tools to be developed
Polar HDF-EOS Website created
•
HDF_EOS IV
http://nsidc.org/PROJECTS/HDFEOS
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