Landsat Image Services Update

[TamaraGrant1]

by Robert Waterman

Released on  April 18, 2018

This release of Landsat Image Services includes some noteworthy updates…

Improvements

• Revised scaling.  The Top of Atmosphere (TOA) reflectance values (which range from 0 – 1 by default) will now be scaled using a range of 0 – 10,000.   These values were previously scaled to 5,000 – 55,000. Some important user considerations…
  • This change will primarily affect image computation and analytics, where numerical and visual results may vary.
  • This change does not impact the visualization of band combinations and indices provided by Esri and does not impact user-defined raster functions which do not involve image computation.
  • The scale range will now be equivalent to other TOA reflectance products, including those provided by the USGS.
  • This change simplifies the computation of indices such as NDVI.
  • Users should account for the revised scaling accordingly.
• Daily updates. The service will now be updated daily. Minimizing the time between data capture and data availability is important for users who rely on the most recent data.
• New QA band. The service will now include a QA band as band 9. This layer is provided with the Collection 1 data for assessing general quality conditions within an image.  For more information, please reference  Landsat Collection 1 Level-1 Quality Assessment.
• New field. Our Landsat Image Services will continue to provide both Pre-Collection and Collection 1 data.  A new field called Landsat_product_id has been added to distinguish between the two. For more on these collections, see Landsat Collections.
• WCS and WMS compatibility. The Landsat Image Services will now include the ability to be consumed as WCS or WMS services.

Affected Apps and Services
Due to the change in output range of pixel values, the image services update will affect users who use the services for processing and analytics. The following apps, services, and tools will be affected.

Apps

• Landsat Explorer, Landsat App
• Minor modifications will be made to the computation of indices.

Services

• Landsat 8 Views, Landsat 8 PanSharpened, Landsat 8 Panchromatic, Multispectral Landsat, Pansharpened Landsat, Panchromatic Landsat, Landsat GLS Multispectral, Landsat GLS Pansharpened, Landsat GLS Panchromatic
• All the functions will be updated resulting in a change in the raw values.
• Web map functionality will not change.

Tools

• Landsat 8 Image Service Add-in Tools
• Minor modifications will be made to the computation of indices. If you are using the Add-in, you will need to update it.