Managing categorical rasters in ArcGIS Workflow

Categorical raster management has been greatly enhanced at ArcGIS 10.1. Multiple rasters that have the same classification scheme can be ingested in a mosaic dataset, share one attribute table and colormap, can be published as a single image service, and can be used as a single dataset.  Below is a workflow of how to achieve this.

1.    Use Create Mosaic Dataset tool to create a new mosaic dataset

2.    Set Thematic as the Source Type, on the Mosaic Dataset Properties page:

3.    Use Add Rasters to Mosaic Dataset tool to add categorical data into the mosaic dataset

4.    In some cases, source rasters may have NoData pixels around the edge (usually 0 or 255) that needs to be filtered out – use the Define Mosaic Dataset NoData tool.

5.    Use the Calculate Statistics on the mosaic dataset. This will give mosaic dataset statistics and histograms.
6.    Add the Attribute table function

7.    Use the Build Overviews tool to create overviews
8.    Optionally you can publish the mosaic dataset as an image service. The raster attribute table, statistics and histograms will be streamed by the image service through its SOAP and REST APIs along with categorical imagery. You can use unique value and classified renderers on both the mosaic dataset and the image service.

Important notes:
Please note the raster value attribute table is used by the mosaic dataset but not stored in the mosaic dataset. So whenever you need to move the mosaic dataset, you need to go to mosaic dataset’s function tab to point to the correct/accessible raster attribute table location.
Also please keep in mind, ArcGIS Server account need access to mosaic dataset, source rasters, and the raster attribute table.


Contributed by: Wenxue Ju

About the author

Simon W

Simon is an Esri product engineer on the Raster team. He works mainly with Pixel Editor, raster visualization, georeferencing, and documentation.

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