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Over the last twelve months the USGS has been working on streamlining and consolidating Landsat Level-1 metadata fields across all sensors in the Landsat archive.  This consolidation effort will ensure consistency for already-archived data, while preparing the archive for the next generation of Landsat missions, starting with the launch of Landsat 9 in December 2020. 

During the week of May 14, 2018, the USGS will finalize this consolidation effort. 

Beginning Monday, May 14, 2018, access to Landsat Collection 1 Level-1 and Level-2 datasets will be intermittently available from all USGS data portals. Landsat 8 and Landsat 7 Collection 1 Level-1 datasets will be fully available on EarthExplorer (EE) by the end of Monday, with Landsat 4-5 TM and Landsat 1-5 MSS becoming available on Tuesday, May 15.  The ordering and processing of Landsat Collection 1 Level-2 on-demand datasets will also resume on Tuesday, May 15. 

After this effort, methods used to access and download Landsat Level-1 products will not change, although some metadata fields will be impacted by this update — including the visible metadata on EE, the metadata downloadable exports from EE, and the metadata downloaded from the Landsat Missions Web Site bulk metadata service.  The following tables display and describe these changes.

NOTE: The Metadata file (MTL.txt) delivered with the Landsat Level-1 products will not be changing.

Users are encouraged to contact us with any questions about the changes and downtime plans.


Landsat Level-1 Metadata Field Changes

The following visible metadata fields have been changed:

EE Metatdata Export
Header Row
LMWS Download Entire
Metadata Field Name
Explanation of Change
Data Type Level-1 DATA_TYPE_L1 EE exports sometimes included a mix of values, such as "L1TP" and "ETM+ L1GT." Going forward, users will see values with the sensor, underscore, and four-letter code, for example:
MSS_L1TP
MSS_L1GS
TM_L1TP
TM_L1GS
ETM_L1TP
ETM_L1GT
ETM_L1GS
OLI_TIRS_L1TP
OLI_TIRS_L1GT
OLI_L1TP
OLI_L1GT
TIRS_L1GT
Gain Change GAIN_CHANGE In Landsat 7 ETM+, there were "Gain Change #" fields for each band indicating whether that band changed from High to Low (or vice versa). This field consolidates those into a 'Y' or 'N' depending on whether any bands changed their gain state during acquisition of that scene. Individual band gain and gain change information remains available in the .MTL file downloaded with the Level-1 product.
Geometric RMSE Model GEOMETRIC_RMSE_MODEL In Landsat data, some scenes previously displayed 0 values that are now NULL in cases where this value is not assessed.
Image Quality IMAGE_QUALITY In Landsat 4-5 TM and Landsat 1-5 MSS data, this field was called Acquisition Quality in the EE metadata export. In Landsat 7 ETM+ data, there were formerly two fields: Image Quality VCID 1 and Image Quality VCID 2 in the EE metadata export, or imageQuality1 and imageQuality2 in the LMWS Download Entire Metadata files. These have been merged into one, displaying the maximum quality score.
NW Corner Lat
NW Corner Long
UL Corner Lat
UL Corner Long
Affects Landsat 7 ETM+, Landsat 4-5 Thematic Mapper, and Landsat 1-5 MSS data only.
Decimal degree fields include ‘dec’ at the end of each field name.
NE Corner Lat
NE Corner Long
UR Corner Lat
UR Corner Long
Affects Landsat 7 ETM+, Landsat 4-5 Thematic Mapper, and Landsat 1-5 MSS data only.
Decimal degree fields include ‘dec’ at the end of each field name.
SW Corner Lat
SW Corner Long
LL Corner Lat
LL Corner Long
Affects Landsat 7 ETM+, Landsat 4-5 Thematic Mapper, and Landsat 1-5 MSS data only.
Decimal degree fields include ‘dec’ at the end of each field name.
SE Corner Lat
SE Corner Long
LR Corner Lat
LR Corner Long
Affects Landsat 7 ETM+, Landsat 4-5 Thematic Mapper, and Landsat 1-5 MSS data only.
Decimal degree fields include ‘dec’ at the end of each field name.

Table 1. Field names  changed in the visible metadata on EarthExplorer, EarthExplorer metadata exports, and files downloaded from the Landsat Missions Web Site bulk metadata service.

Landsat Level-1 Metadata Field Removals

Several fields have been removed from the metadata available through the EE full metadata display and metadata exports, because they are no longer applicable, such as the fields listed in the table below

Metadata Fields Notes
Gain Band 1 through Gain Band 8 No longer included in searchable metadata
Gain Change Band 1 through
Gain Change Band 8
No longer included in searchable metadata; there is a Gain Change
field with "Y" or "N" to indicate whether any bands experience a band
change
Quality Band 1 thorugh Quality Band 8 No  longer included in searchable metadata
Data Category Not included in Level-1 data exports, always NOMINAL
Elevation Source  
Full Aperture Calibration Formerly in Landsat 1-7 metadata
Orientation Always North-Up
Output Format Always GeoTIFF
Resampling Option Always Cubic Convolution

Table 2. Field names removed from the visible metadata on EarthExplorer, EarthExplorer metadata exports, and files downloaded from the Landsat Missions Web Site bulk metadata service.

Landsat Full-Resolution Browse Changes

In the Level-1 Full-Resolution Browse, Landsat 1-7 previously used RGB 0,0,0 to represent the fill areas of the image.  Going forward, the fill will use NoData (see the images below):

These images display the Landsat Level-1 Full Resolution Browse image, and the changes made to the fill areas of the images. The left image displays RGB 0,0,0, while the right image displays the new value of NoData.  These images display the Landsat Level-1 Full Resolution Browse image, and the changes made to the fill areas of the images. The left image displays RGB 0,0,0, while the right image displays the new value of NoData.
Figure 1. These images display the Landsat Level-1 Full Resolution Browse image, and the changes made to the fill areas of the images. The left image displays RGB 0,0,0, while the right image displays the new value of NoData.

 

 

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