Global Land Surveys (GLS)
The Global Land Survey (GLS) data sets were created as collaboration between NASA and the U.S. Geological Survey (USGS), and were designed to allow scientists and data users to have access to a consistent, terrain corrected, coordinated collection of data.
Five epochs have been created, each using the primary Landsat sensor in use at the time:
- GLS1975: uses Multispectral Scanner (MSS) data
- GLS1990: uses Landsat 4-5 Thematic Mapper (TM) data
- GLS2000: uses Landsat 7 Enhanced Thematic Mapper Plus (ETM+) data
- GLS2005: uses a combination of Landsat TM and ETM+ data
- GLS2010: uses a combination of Landsat TM and ETM+ data
These images of New York City, New York and surrounding areas are examples of the Global Land Surveys (GLS) data sets. From left: GLS1975, GLS1990, GLS2000, GLS2005, and GLS1010.
The Landsat data incorporated into each GLS data set meets quality and cloud cover standards, and is processed to the following parameters:
- Data Resolution (Reflective bands): 30 meters (Landsat MSS: 60 meters)
- Data Format: GeoTIFF (Level 1 product), Full-resolution .jpg (LandsatLook images)
- Resampling: Cubic Convolution
- Projection: Universal Transverse Mercator (UTM)
- Datum: WGS84
The Global Land Survey data sets are scene-based, and can be searched and downloaded at no charge from EarthExplorer (http://earthexplorer.usgs.gov/) or GloVis (http://glovis.usgs.gov/).