LandsatLook images are full resolution files derived from Landsat Level 1 data products. The images are compressed and stretched to create an image optimized for image selection and visual interpretation. It is recommended that these images not be used in image analysis.
The files are included as options when downloading Landsat scenes from EarthExplorer (http://earthexplorer.usgs.gov), GloVis (http://glovis.usgs.gov) or the LandsatLook Viewer (http://landsatlook.usgs.gov) (See Figure 1).
LandsatLook download options
LandsatLook "Natural Color" Image:
The LandsatLook “Natural Color” image is a .jpg composite of three bands to show a “natural” looking (false color) image. Reflectance values were calculated from the calibrated scaled digital number (DN) image data. The reflectance values were scaled to a 1-255 range using a gamma stretch with a gamma=2.0. This stretch was designed to emphasize vegetation without clipping the extreme values.
- Landsat 8 OLI = Bands 6,5,4
- Landsat 7 ETM+ and Landsat 4-5 TM = Bands 5,4,3
- Landsat 4-5 MSS = Bands 2,4,1
- Landsat 1-3 MSS = Bands 7,5,4
LandsatLook “Thermal" Image:
The LandsatLook “Thermal” image is a one-band gray scale .jpg image to display thermal properties of the scene. Image brightness temperature values were calculated from the calibrated scaled digital number (DN) image data. An image specific 2 percent clip and a linear stretch to 1-255 were applied to the brightness temperature values.
- Landsat 8 TIRS = Band 10
- Landsat 7 ETM+ = Band 61-high gain
- Landsat 4-5 TM = Band 6
- Landsat 1-5 MSS = not available
LandsatLook “Quality” Image:
LandsatLook “Quality” images are 8-bit files generated from the Landsat Level-1 Quality band to provide a quick view of the quality of the pixels within the scene to determine if a particular scene would work best for the user's application. This file includes values representing bit-packed combinations of surface, atmosphere, and sensor conditions that can affect the overall usefulness of a given pixel. Color mapping assignments can be seen in the tables below.
For each Landsat scene, the LandsatLook Quality Image can be downloaded in the Portable Network Graphics format (_QB.png) individually from EarthExplorer (EE). When the LandsatLook images with Geographic Reference file is selected to download on EE, the Quality Image is provided in GeoTIFF format (_QB.TIF).
Table 1. Landsat 8 Quality Image bit mapping assignments
NOTE: Landsat 4-5 and Landsat 7 Quality images will become available June 2016.
Table 2. Landsat 4-5 and Landsat 7 Quality Image mapping assignments
LandsatLook Images with Geographic Reference:
The LandsatLook Image with Geographic Reference is a .zip file bundle that contains the “Natural Color”, the gray-scale “Thermal” image browse, and the 8-bit “Quality” image in georeferenced GeoTiff (.TIF) format.
LandsatLook “Natural Color” Image: Landsat 8 Path 45 Row 30 Acquired April 23, 2013
LandsatLook “Thermal” Image: Landsat 8 Path 45 Row 30 Acquired April 23, 2013
LandsatLook “Quality” Image: Landsat 8 Path 45 Row 30 Acquired April 23, 2013 with background color set to dark grey.
Additional Information about LandsatLook .jpg images:
Many geographic information systems and image processing software packages easily support .jpg images. To create these files, Landsat data is mapped to a 1-255 range, with the fill area set to zero (if a no-data value is set to zero, the compression algorithm may introduce zero-value artifacts into the data area causing very dark data values to be displayed as no-data.)