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This is a self directed opportunity to examine available data with several visualization and analysis tools. You may go in any order. Experts familiar with the local computer system, the visualization and analysis software packages, and the data sets are available for one on one or small group question and answer throughout the scheduled lab time.
Login details provided on site only!
Start netscape with " netscape & " on the command line.
Your start page should be the BRDF and Albedo page. Click the first workshop link at the center bottom. On the upper left of the MODLAND Workshop page, click on "Tutorials" to get to http://geography.bu.edu/brdf/labdemoinfo.html , this page.
The links below are provided for informational purposes only. Representative data sets have been ordered in advance and there is neither time nor disk space available during this lab for real time custom orders.
The MODIS Home Page, http://modis.gsfc.nasa.gov/ , provides information and links for the entire data product suite in production and development from both the Terra and Aqua orbital platforms for the MODIS instrument.
The Data Pool, http://edcdaac.usgs.gov/tutorial/datapool.html , is a new user interface to a near real time data archive. It is a "drill down" model, in that it is a heirarchy of clickable links from the general to the specific. The final link is a downloadable ftp file. The data sets here are not the complete archive of products, global extent, or full time series available from the EOS Data Gateway.
The EOS Data Gateway, http://edcimswww.cr.usgs.gov/pub/imswelcome/ , is a complete search and order interface for MODIS and other data archived at the USGS Eros Data Center Distributed Active Archive Center. The large volume and variety of available data means that the user must define many decision surfaces to refine the search to reasonable limits. Once a successful search is complete, one formally orders the data on either hard media, ftp pull, or ftp push. There is currently a delay of more than eight weeks for creation and delivery of hard media. There is usually a delay of some hours before email notification that files are mounted for ftp pull. Files remain mounted for 72 hours after email notification of their availability is sent. Sysadmin security concerns generally must be addressed to arrange for ftp push. The Ordering Tutorial for the EOS Data Gateway is at http://edcdaac.usgs.gov/tutorial/index.html .
The MODIS Web Organigram, http://modis.gsfc.nasa.gov/cgi-bin/texis/organigram/weblinks , provides central access to the home pages of the MODIS land products. Each has an online user manual. A guide to MODIS Data Product status is at http://edcdaac.usgs.gov/modis/dataprod.html .
Global Browse Images for MODIS land products are available at http://landqa2.nascom.nasa.gov/browse/ . These images are for a subset of the complete archive available from the EOS Data Gateway.
The MODIS Land Quality Assessment Site, http://landdb1.nascom.nasa.gov/QA_WWW/newPage.cgi , allows users to familiarize themselves with the artifacts, caveats, and idiosyncracies associated with each of the MODIS Land products.
The CD-ROM contents have already been loaded onto the system and are available in "~courseware/data/intro_mmds_set".
If you prefer to verify the contents of the distributed CD-ROM, insert the it in the drive and access it with the path "/CDROM/intro_mmds_set/". The CD-ROM contents are also available online at ftp://modis.gsfc.nasa.gov/pub/Data_Sets/ .
To avoid multi-user collisions, please copy the file you want to look at to the workspace you're in. Please limit yourself to one file at a time. Each of you has a dedicated workspace, always accessible by typing " cd " at the command line.
There are JPEG and HDF-EOS format files on the MMDS disk. To view a JPEG, for example, type
" cp ~courseware/data/intro_mmds_set/land/jpg/albedo/mod43b42.jpg . " (Note: A left-click-and-drag highlights the green text of this command. One may then point the cursor in the terminal window and middle-click to paste this text on the command line).
on the command line, followed by
" xv mod43b42.jpg & "
To view HDF-EOS files directly, use HDFLook, a tool provided on the CD-ROM and installed on the local system. The HDFLook home page is at http://www-loa.univ-lille1.fr/Hdflook/hdflook_gb.html . Users already familiar with ENVI can also access it by typing "envi" on the command line. This is not intended to be an ENVI tutorial, but it's available and you're welcome to use it. Other tools are available as well. Some we know of are listed on the HDF-EOS Tools page of the MODIS MOD12 Land Cover and Land Cover Dynamics Products User Guide, http://geography.bu.edu/landcover/userguidelc/tools.html .
" cp ~courseware/data/intro_mmds_set/land/hdf/albedo/mod43b42.hdf . "
Type and run " HDFLook & ".Select a data directory, if necessary, as this is your own workspace.
Select a file, in this case, "mod43b42.hdf".
In the pop up window; choose the first SDS list.
To view basic metadata, click "Show attributes".
To display an image visualization of the data in the SDS, click "Show SDS as an image".
To adjust the background color, for example, choose "40 Yellow ..." in "Mask values", and change text to "40 Blue ...", then click "Apply".
To adjust the stretch range, type a new value for the "Low cut-off" and "High cut-off" limits, such as 0 for low and 400 for high, then click "Apply".
To quit, click "Close" for all popup Windows and then "Exit".
MODIS land data products are archived in nominal 10° tiles in Integerized Sinusoidal projection. Commercial vendors have been slow to support this projection, so the EDC DAAC wrote a Java tool to allow users to reproject HDF-EOS tiles to other, more widely supported projections and the TIFF data format. The MODIS Reprojection Tool Distribution Page is at http://edc.usgs.gov/programs/sddm/modisdist/index.shtml . Data for this module are in "~courseware/data/NE_tiles/". The available products are MOD09, Surface Reflectance; MOD11, Land Surface Temperature and Emissivity; MOD12, Land Cover Classification; MOD13, Vegetation Indices; MOD14, Thermal Anomalies/Fire; MOD15, Leaf Area Index and Fraction of Photosynthetically Absorbed Radiation; MOD17, Photosynthesis and Net Primary Productivity; and MOD43, Albedo and Nadir BRDF Adjusted Reflectance. They are for coincident time and space, Day 2002241, August 19, 2002, tile h12v04, the northeastern U. S. A. and some of southern Canada. Caution : This module can be very time consuming.
" cp ~courseware/data/NE_tiles/MOD43B4.A2002241.h12v04.003.2002265001546.hdf . "
Type and run " ModisTool & "Click "Open Input File ..."
Select a file, in this case "MOD43B4.A2002241.h12v04.003.2002265001546.hdf".
All the available data layers are selected by default. Select just one band for this exercise to save time.
To move "Selected Bands" to "Available Bands, click on one and then click "<<". To move more than one band at a time, click the name of the firstband in the range you wish to move, scroll until the name of the last band is visible, press and hold the "Shift" key, and click on the last band. Click the "<<" button. This should move all undesired bands to "Available Bands", leaving only one band in the "Selected Bands" list.
Click "Specify Output File". You have complete control of naming your output files. The extension you choose, ".hdr", ".hdf", or ".tif", will determine your output result, and ASCII header imformation file, Heirarchical Data Format file with embedded metadata, or Tagged Image File Format (TIFF).
Choose "Resampling Type" and "Output Projection Type".
Input "Output Pixel Size". This data set is nominal 1km spatial resolution. Both approximately equal size and sub pixel resolutions take a longish time to process, so use a coarser resolution such as 0.1° or 10km.
Click "Run" to reproject the image. A pop up shows status and progress.
Use the appropriate viewing software as in module #2 to examine the output.
Not all MODIS products are in Integerized Sinusoidal projection. The National Snow and Ice Data Center (NSIDC), for example, deals with polar regions, and with Level 0, Level 1, and Level 2 swath data before it's been processed to the ISIN grid. They developed the MODIS Swath-to-Grid Toolbox, MS2GT. (Home page: http://nsidc.org/PROJECTS/HDFEOS/MS2GT/ .) Products that this tool is useful for include MOD02, Level 1B Calibrated Radiances; MOD03, Level 1A Geolocation Fields; MOD10, Level 2 Snow Cover; and MOD29, Level 2 Sea Ice Extent. The toolbox comes packaged with an HTML formatted manual and tutorials.To access the manual in Netscape, click on "File", then "Open Page", then choose "ms2gt", then "doc", then "index.html".
The executable, parameter, and data files for the tutorials are linked into the four tutorial subdirectories in your subdirectory called "ms2gt".
" cd ms2gt/tutorial_4 " (Due to the size of the output files in tutorials 1 & 2, we request you start with tutorial 3 or 4 while here at our facility. Thank you.)
" *.csh "
Continue as desired with the NSIDC tutorial intructions.
Last update: 22 October 2002 by John Hodges
Up to the MODIS Workshop on Land Surface
Radiation Budget Variables
and Snow and Ice Products
Main Page