The Landsat MSS products are being reprocessed as part of the SLAP project, and will be released to the users progressively during the third quarter of 2019.

There are two types of reprocessed MSS Level 1 Landsat product that will be available for user download:

• Precision Ortho-Corrected Level 1 Product (L1T): Level 1 Terrain corrected product; The most accurate level of processing as they incorporate Ground Control Points (GCPs) and a Digital Elevation Model (DEM) to provide systematic geometric and topographic accuracy; with geodetic accuracy dependent on the number, spatial distribution and accuracy of the GCPs over the scene extent, and the resolution of the DEM used.
• Improved Level 1 Product (L1G+): L1G+ is an intermediate accuracy product generated when the estimated geolocation error using GCPs is too low to produce a L1T and does not allow the use of a DEM. These are often scenes in which few or no reliable GCPs have been identified within the scene. In the latter case GCPs identified in adjacent scenes are used to improve the geolocation of the product.
• Basic Level 1 Product (L1G): Level 1 Geo-coded product; Normally generated where there is a lack of GCPs, and are derived purely from data collected by the sensor and spacecraft e.g. ephemeris data.

For FAQs regarding the Landsat missions, see the USGS website.

MSS - Algorithm Information (applicable to IPF v3.08)

The European Space Agency (ESA) has acquired Landsat data over Europe through the ESA ground stations during the last 40 years, in co-operation with the USGS and NASA. In 2014, the product generation system of ESA has been significantly improved for supporting the Landsat MSS, TM and ETM+ archive reprocessing [ESA-S2-Symp-2014] and aligning historical Landsat data to Landsat-8 and Sentinel-2.

In terms of products and algorithms, the approach of ESA and the USGS is now similar and ESA algorithms are mostly based on the USGS ones. Developments of the ESA software include the following improvements, and are discussed in detail in the European Space Agency (ESA) Landstat MSS/TM/ETM+ archive bulk-processing: processor improvements and data quality document.

• Multi-scene refinement processing
• Extension of the Terrain Corrected Processor above 60° North
• MSS geometric and radiometric improvements
• MSS cloud cover assessments

For details of the algorithms, radiometric and geometric processing of the ESA Landsat MSS products, see the Landsat Products, Algorithms and Processing Document.

Landsat Technical Documents

Level 0

• ACS WILMA Format: Description of the ACS WILMA format of the Level 0 products, with which the ESA Landsat processor ingests
• Ground radiometric processing procedures: Document describing the ground radiometric processing procedures of the MSS products
• Landsat to Ground Station Interface Description: Description of the MSS telemetry format.

Level 1

• Landsat Products Description Document: User guide to the ESA Landsat MSS, TM and ETM+ archives for v3.03 of the Landsat IPF. A new of PDD will be available soon.
• Landsat MSS Data Format Control Book (DFCB): USGS Level 1 product specification, with which the ESA reprocessed MSS products are compliant.
• ngEO Tailoring for Landsat: Description of the preliminary tailoring of the Next Generation User Services for Earth Observation (ngEO) concepts towards Landsat 1-7 missions, with which the ESA reprocessed product Metadata and Quick Look are compliant.
• ngEO Browse Report File Generic Interface (BRGICD): Statistical description of the ngEO Generic Browse Report File.