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Some tips on  searching for data using Earthdata Search.


In General:

The free text field works best when searching for a specific collection by collection name, shortname, collection id or project name.   While it will attempt to understand natural language queries like " land surface temperature over Uganda for the last 10 years," the algorithm is not yet perfected, and often returns sub-optimal results.

If you don't know the collection or project name, it is recommended instead to start your search using the search "facets" (aka checkboxes) on the left to specify keywords, projects, etc., and then enter your spacial and date criteria using the spacial and date criteria icons located just to the right of the free text field.

So for example, to search for "land surface temperature over Uganda for the last 10 years,"

  1. Check the following checkboxes on the left:
    Keywords | Land Surface | Land Temperature
    Keywords | Surface Radiative Properties | Land Surface Temperature
    Keywords | Surface Thermal Properties | Land Surface Temperature
  2. Enter date criteria:  click the clock icon next to the free text field, and enter Start: 2008-01-01 00:00:00 and Stop: Today.
  3. Enter spacial criteria:  click the compass icon next to the free text field, and draw a bounding rectangle around Uganda.

Recurring date example:  How to search for all Novembers from 2000 to 2018:

  1.  In the upper left corner of the screen, click the temporal icon (the clock).
  2. In the dialog, check "Recurring"
  3. In the dialog, click in "Start," then click "Nov," then click "1"
  4. In the dialog, click in "End," then click "Nov," then click "30"
  5. In the dialog, adjust "Year Range" to be 2000 - 2018  
  6. In the dialog, click "Apply Filter"

Entering grid coordinates: coordinate system options

CALIPSO
Dimensions - Orbit/Path
Enter orbit and path coordinates separated by spaces, e.g. "2,3 5,7 8,8"
Note - Orbit and Path values are not continuous and cannot be used in a range.
More info:
https://www-calipso.larc.nasa.gov/resources/calipso_users_guide/faq.php

MISR
Dimensions - Path/Block
Enter path and block coordinates separated by spaces, e.g. "2,3 5,7 8,8"
Note - Path values are not continuous and cannot be used in a range.
More info:
https://eosweb.larc.nasa.gov/
https://eosweb.larc.nasa.gov/sites/default/files/project/misr/guide/MISR_Science_Data_Product_Guide.pdf

MODIS EASE
Dimensions - Horizontal/Vertical
Enter h and v coordinates separated by spaces, e.g. "2,3 5,7 8,8"
More info:
"For MODIS Sea Ice EASE-Grid products. Tiles are 951 pixels x 951 pixels and 10 degrees by 10 degrees, with half of the tiles (313) located in the north polar grid and half in the south polar grid. In addition:

    • The north polar grid tile coordinate system starts at (0,0) (horizontal tile number, vertical tile number) in the upper left corner and proceeds right (horizontal) and downward (vertical). The tile in the bottom left corner is (18,18).
    • The south polar grid tile coordinate system starts at (0,20) and the tile in the bottom left corner is (18,38).
    • The polar grids are based on the Lambert Azimuthal Equal Area map projection centered on each pole. The grids are compatible with the NSIDC EASE-Grid."

https://nsidc.org/data/modis/ease-grid-tile-locations-sea-ice
http://nsidc.org/data/ease

MODIS Sinusoidal
Dimensions - Horizontal/Vertical
Enter h and v coordinates separated by spaces, e.g. "2,3 5,7 8,8"
More info:
"MODIS Land products use the Sinusoidal grid tiling system. Tiles are 10 degrees by 10 degrees at the equator. The tile coordinate system starts at (0,0) (horizontal tile number, vertical tile number) in the upper left corner and proceeds right (horizontal) and downward (vertical). The tile in the bottom right corner is (35,17)."
http://spatialreference.org/ref/sr-org/modis-sinusoidal/
https://modis-land.gsfc.nasa.gov/MODLAND_grid.html
https://lpdaac.usgs.gov/dataset_discovery/modis

WELD ALASKA Tile
Dimensions - Horizontal/Vertical
Enter h and v coordinates separated by spaces, e.g. "2,3 5,7 8,8"
More info:
A U.S. Landsat ARD 30m tile system based on the Web-Enabled Landsat Data (WELD) project, with coordinates anchored in ALASKA.


Upper Left Tile (ul corner)
Lower Right Tile (lr corner)

(h)(v)ulX (m)ulY (m)(h)(v)lrX (m)lrY (m)
Alaska00-851715247432516131698285374325

https://landsat.usgs.gov/what-us-ard-tile-grid
https://landsat.usgs.gov/ard#Tile%20Grid

WELD CONUS Tile
Dimensions - Horizontal/Vertical
Enter h and v coordinates separated by spaces, e.g. "2,3 5,7 8,8"
More info:
A U.S. Landsat ARD 30m tile system based on the Web-Enabled Landsat Data (WELD) project, with coordinates anchored in CONUS (the continental U.S.)


Upper Left Tile (ul corner)
Lower Right Tile (lr corner)

(h)(v)ulX (m)ulY (m)(h)(v)lrX (m)lrY (m)
CONUS00-256558533148053221238441514805

https://landsat.usgs.gov/what-us-ard-tile-grid
https://landsat.usgs.gov/ard#Tile%20Grid

WRS-1 (Landsat 1-3)
Dimensions - Path/Row
Enter path and row coordinates separated by spaces, e.g. "2,3 5,7 8,8"
More info:
"The Worldwide Reference System (WRS) is a global notation used in cataloging Landsat data. Landsat 8 and Landsat 7 follow the WRS-2, as did Landsat 5 and Landsat 4. Landsat 1, Landsat 2, and Landsat 3 followed WRS-1.""
https://landsat.usgs.gov/what-worldwide-reference-system-wrs

WRS-2 (Landsat 4+)
Dimensions - Path/Row
Enter path and row coordinates separated by spaces, e.g. "2,3 5,7 8,8"
More info:
"The Worldwide Reference System (WRS) is a global notation used in cataloging Landsat data. Landsat 8 and Landsat 7 follow the WRS-2, as did Landsat 5 and Landsat 4. Landsat 1, Landsat 2, and Landsat 3 followed WRS-1.""
https://landsat.usgs.gov/what-worldwide-reference-system-wrs

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