Starting in July 2012, the GLS Landsat services that Esri hosts have been enhanced with the improved support for Landsat satellite imagery in ArcGIS 10.1. Currently, Esri makes five different epochs of this imagery available as image services: for 1975, 1990, 2000, 2005, and 2010.
These collections are managed and processed using mosaic datasets. They are then made available as image services using ArcGIS for Server. Improvements and added capabilities to both mosaic datasets and the image services have resulted in the improved Landsat services.
Additional raster types allow us to fully support all the Landsat products from Landsat 1 to 7, supporting MSS, TM, and ETM+ imagery.
Using the Landsat sensor's metadata allows applications to manage information about the data, use it to improve the display, and enable the use of new functions, such as Apparent Reflectance and Tasseled Cap. The Apparent Reflectance function allows the application to radiometrically calibrate the data which makes the images more useful in analysis applications and results in better color balancing across the collection.
Improvements to the Mask function allow it to be used as part of a process chain to remove the Scan Line Corrector (SLC) gaps from the more recent Landsat 7 ETM+ imagery (post 2003).
Additional functions, such as Tasseled Cap, allows Esri to produce more analysis products.
With improvements to ArcGIS for Server and the 64-bit processing, image services are faster. Server-side functionality has been expanded to allow you to use all of the on-the-fly processing you can apply to images in Desktop to image services. This allows Esri to provide many more imagery products from the Landsat imagery and allows us to reduce the number of individual image services. Multiple services are still available; however, you can connect to just one service and access and choose different products through the properties.
Since the image services have been improved with new and enhanced processing, better results are derived in the Change Matters web application.