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The Polar HDF-EOS Data Imaging and Subsetting (PHDIS) Tool

Siri Jodha Singh KhalsaEmergent Information Technologies, Inc.

National Snow and Ice Data Center,

University of Colorado

khalsa@colorado.edu

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Genesis – ESDIS Prototype

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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Realize the promise of HDF-EOS

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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DAAC Perspective

Be able to provide a single tool for all polar gridded DAAC data sets• Heritage: AVHRR, SSM/I, TOVS• Future: MODIS, AMSR, GLAS

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Demonstration

The Polar HDF-EOS Data Imaging and Subsetting Tool• IDL-based (multi-platform)

For any HDF-EOS file a user can:• 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

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

Selecting Data to Load

Available fields from all selected files are displayed along with projection information.

Clicking on a field name loads it.

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

Initial Display

Data displayed with gray scale palette.

Mode menu changes click action• Toggle images• Define zoom box• Browse: select

between multiple zoom boxes.

Metadata is read and displayed. User then

selects field(s) to load.

User first selects one or more files

to open.

Top level window is scaled to fit user’s display while showing entire data array. User can load multiple fields and toggle between them or display them in new windows.

Multiple ROI boxes can be registered. Contents visualized in new window and can be displayed in a table.

Instructions for defining a region of interest (ROI) in any visualization window. Box parameters displayed while user positions box.

Table of values includes location and size of selected region.

Selecting “View Image Data” brings

up window from which user selects field to visualize.

Double clicking in a box brings up this menu. (Print and Write to File will be added.)

Image with Legend

Includes palette and a thumbnail image locating the current window in overall array if zoomed.

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New Features to be Added

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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Conclusions

HDF-EOS enables discipline-specific tools to be developed

Polar HDF-EOS Website created• http://nsidc.org/PROJECTS/HDFEOS