An Introduction to MODIS Version 6 Data

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Detailed Description

This video focuses on the National Aeronautics and Space Administration’s (NASA) Terra and Aqua Moderate Resolution Imaging Spectroradiometer (MODIS) Version 6 land data distributed by NASA’s Land Processes Distributed Active Archive Center (LP DAAC). This video will cover how to learn more about MODIS Version 6 data using the LP DAAC website, the MODIS file naming convention, and the external metadata. For more information on MODIS Version 6 data and other data distributed by the LP DAAC please visit https://lpdaac.usgs.gov/. The LP DAAC is one of twelve NASA Earth Observing System Data and Information System (EOSDIS) DAACs. It is located at the USGS Earth Resources Observation and Science (EROS) Center in Sioux Falls, South Dakota. The LP DAAC ingests, archives, processes and distributes NASA Earth science land processes data and information. 

Details

Image Dimensions: 480 x 360

Date Taken:

Length: 00:05:51

Location Taken: Sioux Falls, SD, US

Video Credits

Visual Storyline and Content: Danielle Golon, USGS EROS (Contractor)

Transcript

An Introduction to MODIS Version 6 Data. Presented by the Land Processes Distributed Active Archive Center (LP DAAC). The Moderate Resolution Imaging Spectroradiometer – or MODIS - instrument operates on both NASA’s Terra and Aqua spacecraft. The orbit of each spacecraft allow MODIS to capture the entire Earth every one to two days, providing data products with spatial resolution ranging from 250 to 5,600 meters. The LP DAAC currently distributes more than 100 MODIS Version 6 products covering Surface Reflectance, Temperature, and more. This video will cover how to learn more about MODIS Version 6 data using the LP DAAC website, the MODIS File Naming Convention, and the external metadata. One of the first places to learn more about MODIS Version 6 data is the LP DAAC’s website: lpdaac.usgs.gov. In-depth information about MODIS Version 6 data can be found under the “Dataset Discovery” tab. Hover over “Dataset Discovery”, then hover over “MODIS” and click on the “MODIS Products Table”. The “MODIS Products Table” lists all of the MODIS products distributed by NASA’s LP DAAC. Click on the “Version 6” tab to see the MODIS Version 6 products. The table provides information on the product short name, the dataset, the product, the pixel size, and the temporal granularity. The searchable table allows users to search for specific data products in the MODIS product table. For example, type in “leaf” to bring up Leaf Area Index data from the Terra satellite (MOD), the Aqua satellite (MYD), and data that are combined from both satellites (MCD). Type in the specific short name of a product to find that product. For example, type in MOD09A1. Clicking on the hyperlinked name leads to more product information. All of the MODIS Version 6 Digital Object Identifier (DOI) Landing Pages have the same layout. At the top of the DOI Landing Page is the product short name and the product long name. The “Description” section contains a brief description of the product, as well as any improvements or changes since the previous version of the product. The description section also contains the necessary information for properly citing the data product and a citation generator. To the right of the description section is a visual example of the product tile, a brief informational outline about the product, and the tools that can be used to access the data. The next section of the DOI landing page describes “Characteristics” of the data, including high level information about the collection – or product family - and the granules in the collection. Below that is information about each of the data layers contained in the Hierarchical Data Format (HDF) file. This section also provides links to information about the product quality, which looks at quality control aspects of each pixel in the product, and any known issues with the data. The third section provides links to documentation that relates to that specific data product. These documentation sources include the User Guide which provides a more in-depth and up-to-date explanation of the product and the Algorithm Theoretical Basis Document (ATBD) which provides descriptions of the algorithms and calculations that are fundamental to the product. The fourth section lists the data tools that provide users with access to download and explore the data product. This section also contains data service tools that allow users to manipulate data before downloading any files. Some of these services include reprojection, subsetting the data layers, and downloading data in a different file format. The final section provides resources from the E-Learning page. These resources include tutorials, use cases, scripts, videos, and past webinars and presentations that relate to the data product. The E-Learning table is searchable. For example, type “AppEEARS” in the search bar to bring up the E-Learning resources that relate to the product and AppEEARS. In this case, the resources include a video about accessing MODIS data with AppEEARS and a python tutorial on using the AppEEARS Quality Service to decode MODIS quality information. Now that the product information on the LP DAAC website has been explained, information on how to read the MODIS filename will be discussed. The MODIS filename itself can tell users a lot about the granule without needing to preview it. Here is an example of a Granule ID. The first part of the Granule ID is the product short name. The second part indicates the Julian date of acquisition. The third part indicates the location of the granule, based on the MODIS sinusoidal Horizontal-Vertical tile system. The H/V grid is accessible on the MODIS overview page on the LP DAAC’s website. The fourth part indicates the product version. The fifth part indicates the Julian date of production including the year, day, hours, minutes, and seconds. The last part is the file format. MODIS Version 6 are provided as an HDF file. Another great place to find information about the data is the external metadata file in XML format. The XML file is available through any data access client used to download MODIS Version 6 data. The metadata is data about the data. It provides useful information about a specific granule. The metadata includes the data product DOI link, which is needed to properly cite the data. It also provides information ranging from the granule’s corner coordinate boundaries to the input granules for multiday products. Thank you for watching our video. To learn more about MODIS Version 6 please visit our website at lpdaac.usgs.gov.