LP DAAC distributes ASTER land data processed to Level 1 through 3:

• Level-1A: Reconstructed, unprocessed instrument data at full resolution, time-referenced, and annotated with ancillary information, including radiometric and geometric calibration coefficients and georeferencing parameters (e.g., platform ephemeris) computed and appended but not applied to Level 0 data.
• Level-1B: Level-1A data that have been processed to sensor units (not all instruments have Level 1B source data).
• Level-2: Derived geophysical variables at the same resolution and location as Level-1 source data (swath products).
• Level-3: Variables mapped on uniform space-time grid scales, usually with some completeness and consistency.

The ASTER products have two sources of metadata: the embedded Hierarchical Data Format (HDF) metadata, and the external Earth Observing System Data and Information System (EOSDIS) metadata, otherwise known as the EOSDIS Core System (ECS) metadata. The generated ECS .met file is the external metadata file in XML format that is delivered to the user along with the ASTER product. For georeferencing purposes, use the values delineated in the embedded HDF metadata. Other product-specific and core metadata can be referred from either source.

Refer to the ASTER User Handbook for L1B products and the User Guide for higher level products regarding details on the individual core and product metadata attributes.