Imagery & Remote Sensing

New Enhancements to Ocean Content in the Living Atlas of the World

New enhancements to Ocean Content in the Living Atlas of the World

The Living Atlas team is excited about the most recent ocean content release.  With 1 new service and significant enhancements to 7 additional services this update improves performance and expands analytical capabilities. The new and updated services include:

Distance to Coast (new)

Distance from Shore (updated)

Seafloor Aragonite (updated)

Seafloor Bathymetry (updated)

Seafloor Dissolved Oxygen (updated)

Seafloor Salinity (updated)

Seafloor Silicate (updated)

Seafloor Temperature (updated)

Enhancements and Explanations

Raster Functions:  This release adds raster functions to many of the ocean services. When you publish an image service you can define functions that are applied by the server on the fly when requested by a client application. To learn more, see Server-side processing with raster functions.
This release of Oceans Content includes the following functions:

Aspect Function

Hillshade Function

Slope Function

Unit Conversion Function (meters to feet)

Unit Conversion Function (Celsius to Fahrenheit)

 Unit Conversion Function (Celsius to Kelvin)

Unit Conversion Function (kilometers to miles)

Color Map Function (Cartographic Renderer)

Color Map Function (Classified Renderer)

Raster Function Templates may be activated in ArcMap by loading the service into the map, right clicking on the service in the Table of Contents to select Properties, and selecting the desired function from the Server Functions tab.  For help with invoking raster functions via REST calls, see http://resources.arcgis.com/en/help/rest/apiref/.

For more information on raster functions and raster function templates please see the following links:

http://server.arcgis.com/en/server/latest/publish-services/linux/server-side-raster-functions.htm

Below is a listing of the services and associated raster functions.

Distance from Shore

Distance to Coast

Seafloor Aragonite (updated)

Seafloor Bathymetry (updated)

Seafloor Dissolved Oxygen (updated)

Seafloor Salinity (updated)

Seafloor Silicate (updated)

Seafloor Temperature (updated)

Compression:  The source data for the services is scientific in nature and has a large pixel depth (32-bit or 16bit).  In previous releases LZ77 was used as the default compression.   In this release we utilized the LERC compression and kept the data at the native pixel depth.

LERC—Limited Error Raster Compression (LERC) is an efficient lossy compression method recommended for single-band or elevation data with a large pixel depth, such as float, 32-bit, 16-bit, or 12-bit data. LERC compresses 5 to 10 times better and 5 to 10 times faster than LZ77 for float data. LERC is also better with integer data. When using integer data, and the error limit specified is 0.99 or less, LERC is considered a lossless compression.

http://server.arcgis.com/en/server/latest/publish-services/linux/available-map-and-image-cache-properties.htm

https://github.com/Esri/lerc

In previous releases the data had been converted from 32bit to 16bit and then a value attribute table (VAT) was built to support querying as well as color mapping.  This made the service slow when loading in a map.  This also had drawbacks for analysis as the pixel values did not represent the actual data values which were stored in the VAT.

Living Atlas Community

Useful Links

About the author

Keith is a Product Engineer at Esri. He serves as the Ocean Curator for the Living Atlas of the World team. Keith works to create foundational layers that can help marine researchers, scientist, and others gain a better understanding of our oceans.

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