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EDG Data Set Name
ASTER On-Demand L2 Decorrelation Stretch VNIR

Granule Shortname
AST_06VD

Data Set Characteristics
Area: ~60 km x 60 km
Image Dimensions: 4200 rows x 4980 columns
File Size: ~85 Megabytes
Spatial Resolution: VNIR: 15 m
Projection: Universal Transverse Mercator (UTM)

Data Format:	HDF-EOS
	GeoTIFF

Vgroup Data Fields: 3

Product Description
The ASTER On-Demand L2 Decorrelation Stretch VNIR is an on-demand product with user-specified processing options. This product is a color-enhanced image of the VNIR radiance data, which itself is derived from ASTER Level-1B data. Decorrelation stretch is a process used to enhance the color differences in an image by removing the inter-band correlation in the radiance values of the input VNIR pixels. Such an image provides a general overview that emphasizes reflectance variations and restrains variations owing to topography and temperature. The general purpose of a decorrelation stretched image is to serve as a data visualization tool while reviewing and selecting ASTER image data for further analysis and research. It attempts to address three broad requirements of such a visualization tool:

• How well does the image spectrally discriminate among different feature types?
• How consistent are the color, brightness, and spectral signatures across time and space?
• How consistent is the information in the image compared to other satellite images, maps, and aerial photographs?

The decorrelation stretch product algorithm calculates the principal components of a three-band VNIR image. Each component is rescaled or contrast stretched by normalizing the variances of the vectors, and rotated back into the RGB color space.

Vgroup Data Fields/ Spectral Range (Μ)	Units	Data Type	Valid Range	Band Scale Factor
VNIR (15 Meters)
Band 1 (0.52 - 0.60)	None	8-bit unsigned integer	0 - 255	1.0
Band 2 (0.63 - 0.69)	None	8-bit unsigned integer	0 - 255	1.0
Band 3N (0.78 - 0.86)	None	8-bit unsigned integer	0 - 255	1.0

View a Version Formatted for Printing

Ordering ASTER On-Demand L2 Decorrelation Stretch VNIR Product
The ASTER Surface Reflectance VNIR product can be ordered through the EOS Data Gateway. The process and procedures for ordering this product are described in the following tutorial: http://lpdaac.usgs.gov/tutorial/. As part of that process, it is necessary to first select an ASTER Level 1A granule from the EOS Data Gateway.

Product Information

Release Notes (http://asterweb.jpl.nasa.gov/content/03_data/01_Data_Products/release_aster_surface_reflectance.htm)

ASTER Level-1 Data Products Specification (http://asterweb.jpl.nasa.gov/content/03_data/04_Documents/ASTER_L1_Product_Spec_Ver_1.3_July01.pdf)

ASTER User Handbook (http://asterweb.jpl.nasa.gov/content/03_data/04_Documents/aster_user_guide_v2.pdf)

ASTER Level-1 Users Guide (http://www.science.aster.ersdac.or.jp/en/documnts/users_guide/index.html)

ASTER Higher-Level Product User Guide (http://asterweb.jpl.nasa.gov/content/03_data/04_Documents/ASTERHigherLevelUserGuideVer2May01.pdf)

Algorithm Theoretical Basis Document (ATBD) (http://eospso.gsfc.nasa.gov/eos_homepage/for_scientists/atbd/docs/ASTER/atbd-ast-06.pdf)

ASTER JPL Web Page (http://asterweb.jpl.nasa.gov/data_products.asp)

EOS Data Products Handbook (Volume 1, Revised 2004) (http://eospso.gsfc.nasa.gov/ftp_docs/data_products_1.pdf)

Contact Information

LP DAAC User Services U.S. Geological Survey (USGS) Earth Resources Observation and Science Center (EROS) 47914 252nd Street Sioux Falls, SD 57198-0001
Phone:	605-594-6116
Toll Free:	866-573-3222
	866-LPE-DAAC
Fax:	605-594-6963
Email:	LPDAAC@eos.nasa.gov
Web:	http://LPDAAC.usgs.gov

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