The sensor viewing and solar illumination geometry vary with time and location due to the position and movement of the sun the position, orientation, and movement of the satellite and the location of the imaged object on the (rotating) Earth’s surface.The following technical details determine the outcome of the view angle bands for the product in which they are generated: Users of these tools, particularly those who rely upon the sensor viewing angles, should download and use the updated versions of these tools. Please visit the Landsat Sensor Viewing Angle Bands Known Issues page for more details about this issue. The Landsat 4-7 Angles Creation Tool has been updated to correct for this issue. This has been corrected in Landsat Collection 2 and will not impact the angle bands which are bundled as part of the Collection 2 Level-1 products. Collection 1 Landsat 8 data products are not impacted by this issue. The more widely used solar angle bands which are used to perform per-pixel solar corrections for Top-of-Atmosphere (TOA) reflectance conversion are impacted, though it is less visible. In April 2020, the USGS identified an issue with the Landsat Angles Creation Tools which are provided to help some users generate solar illumination and sensor viewing angle bands from the angle coefficient file provided with Collection 1 Landsat 4-7 Level-1 products. Under certain circumstances, there can be discontinuities in the sensor zenith and azimuth bands generated by these tools. Some applications require additional information about the scene geometry – including elevation, slope / aspect, sensor viewing angles (elevation and azimuth), and/or solar illumination angles. The data are precisely registered to a Universal Transverse Mercator (UTM) (or for Antarctica, Polar Stereographic (PS)) map projection grid, making it straightforward to construct pixel ground coordinates from the product corners. These can be converted to at-sensor radiance or reflectance using the additive and multiplicative scaling parameters contained in the metadata file that is delivered with the products. Landsat Collections Level-1 products contain radiometrically and geometrically corrected image data for each spectral band and are delivered as fixed point digital numbers (8-bit for Landsat 4-5 and Landsat 7 16-bit for Landsat 8-9). The sensor and sun viewing angle generation tools and documentation can be found at the bottom of the page. This page describes the architecture and dependencies of sensor and sun angle viewing angles. The output files of these tools, termed as “angle bands,” are images that contain the solar and sensor viewing angles. To learn more about May's life in and outside of Queen, including a technical explanation of the hit song "We Will Rock You," check out the full interview.The angle coefficient file is used as input into tools that allow users to generate sensor and sun viewing angles. The book even includes a collapsible, focusable stereoscope developed by May. After years of research, May published his magnum opus in 2009 - a history of T.R. May and his research partner posted Williams' stereographs online, using crowdsourcing to encourage readers to geotrack and date the images. "I felt drawn to Williams as an artist," he writes in the book's introduction, "perceiving an uncanny parallel between his world, balanced on that fine line between 'art for art's sake' and art for an audience, and my own world, in rock music." In his travels, he began hunting for images taken by one photographer whose name kept recurring: T.R. Through the years, May's interest in stereographs became more specific - and more serious.
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