Knowledge Base

How can I search and order MEaSUREs Greenland Ice Velocity: Selected Glacier Site Velocity Maps with spatial and temporal filtering using Earthdata Search?

NASA Earthdata Search is a map-based search and order tool, allowing you to search for MEaSUREs Greenland Ice Velocity data based on spatial and temporal constraints. Additionally, you can subset files based on spatial bounding box, and temporal range.

Step 1: Go to Earthdata Search
From https://nsidc.org/data/nsidc-0481 under “Get Data” select “Package” on the upper right side of the webpage and then select the Earthdata Search hyperlink in the pop up window that appears in the center of the screen.

A new tab will open and you will be presented with a view of the Earthdata Search interface with the MEaSUREs Greenland Ice Velocity data set selected.

Step 2: Filter results by spatial or temporal constraints 

If you are interested in filtering the data by a time period or region of interest, you can use the Temporal and Spatial filter options next to the search bar at the top of the page. 

Temporal Filtering
Clicking on the Start and End boxes allow you to drill down to the beginning and end dates of interest. MEaSUREs Greenland Ice Velocity: Selected Glacier Sites from InSAR were collected from January 2009 to present and are frequently updated with new data.

Spatial Filtering
The Spatial filter includes several options for filtering, located next to the temporal filter. The rectangle option results in a map drawing tool, allowing you to draw a bounding box on the map. You can also write in the Southwest and Northeast points underneath the search box if you have specific coordinates of interest. For best results, enter a bounding box of at least 0.5° x 0.5°. 

Using Wildcards to Search by Predefined Grid
The use of wildcards can be applied to search and filter by filenames:

  • Use * (asterisk) to match any number of characters in the filename
  • Use ? (question mark) to match any one character.

Delimiters (space, comma, or new line) can be used to search on multiple files. For example, to search all granules in NSIDC-0481 grid W69.10N use *W69.10N* in the Granule Search box. To add all granules in grid E62.10N to the same search use *W69.10N*, *E62.10N*.    

A table describing the grids in the data set is available at:
https://nsidc.org/data/nsidc-0481?qt-data_set_tabs=2#title7

Step 3: Download
Click on the green "Download Data" button. You will be directed to the Earthdata Login authentication page. Enter your Earthdata Login username and password, or register for a new account if needed.

You will then land on the Data Access page, providing information on the data granules requested and data access methods.

Direct Download provides you with two options:

  1. A list of URLs to download the data matching your spatial and temporal filters. You can download the data directly in the browser, or save the URL list as a file that can be used with WGET or cURL to download from a command-line interface.
  2. A shell script you can save and use in shell terminal to download the data matching your spatial and temporal filters. 

Stage for Delivery offers the ability to order the files, which will be staged to an HTTPS location for you to download, and will also include a zip file containing all of the data in your order.

Last updated: 21 December 2017

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