Global Land Surveys (GLS)
The Global Land Survey (GLS) data sets 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/).