LandsatLook images are full resolution files that are included as options when downloading Landsat data from EarthExplorer (http://earthexplorer.usgs.gov), GloVis (http://glovis.usgs.gov) or the LandsatLook Viewer (http://landsatlook.usgs.gov).
Derived from Landsat Level 1 data products, these images are useful for image selection and for visual interpretation. The JPEG compression algorithm causes minor smoothing of the data which should not affect image interpretation. However, these JPEG compressed images should not be used in digital analysis.
These LandsatLook products are available to download:
The Landsat 8 Geographic Reference bundle also includes the 8-bit quality band (.png) generated from the 16-bit quality band. The 8-bit quality band includes values representing bit-packed combinations of surface, atmosphere, and sensor conditions that can affect the overall usefulness of a given pixel.
The table below gives the bits and colors associated with the 8-bit quality band:
|8-Bit LandsatLook QA Band - Read bits from RIGHT to LEFT <- starting with Bit 0|
|Description||Cloud*||Cirrus*||Snow/Ice*||Vegetation*||Water*||Terrain Occlusion||Dropped Frame||Designated Fill|
|*Set for highest confidence value (11)|
*GDAL XML and ESRI™ referencing systems demonstrate high standards. ESRI™ world files are simple and widely supported, but do not include projection information. GDAL XML files are less well supported, but contain important projection information.
Additional Information about LandsatLook images
About .jpeg images: Most geographic information systems and image processing software packages easily support .jpeg images. To create the .jpeg images, the 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. Other image formats support a layer that explicitly defines the mask area. (Two examples are PNG and JPEG2000. The PNG algorithm creates much larger images. The JPEG2000 algorithm is not as widely supported.)
Top of Atmosphere (TOA): Reflectance values were calculated from the calibrated scaled 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.
Thermal band Units: Image brightness temperature values were calculated from the calibrated scaled DN image data. An image specific 2% clip and a linear stretch to 1-255 were applied to the brightness temperature values.