Road Ahead – New workflow for mosaicking raster datasets

The following post was written by Simon Woo, a product engineer on the geodatabase team specializing in Raster support in the geodatabase.

Previous versions of ArcGIS have provided various mosaicking workflows.  We’ve tried to make the mosaicking experience better in each version, but have had varying feedback on performance, especially when outputting to a file format. 

Prior to ArcGIS 9.3, the workflow to create a mosaic was to create a raster dataset and then use the Workspace to Raster Dataset tool to populate the new dataset.

In ArcGIS 9.3, we have provided a new workflow to make your mosaicking experience faster. 

The new workflow is to:

  • Create an unmanaged raster catalog with the Create Raster Catalog tool.
  • Load all the raster datasets into the unmanaged raster catalog with the Raster to Geodatabase tool.
  • Use the Raster Catalog to Raster Dataset tool to mosaic the datasets together. 

From the tests that we have run, this new workflow is considerably faster.  Below are a couple examples of comparison tests that have been run.   

Mosaic Test 1

Here’s the test data we used:
Type of data: 3-band
Input format: TIFF
Number of files: 20
Average file size: 38.8 MB
Output format: TIFF


 

Using the old workflow of creating a raster dataset and then using the Workspace to Raster Dataset tool, this data took 1 hour and 35 minutes to mosaic.

Here are the steps with the new workflow:

First create an unmanaged raster catalog.

This creates an unmanaged raster catalog. Now load the data into the new unmanaged raster catalog:

Now use the Raster Catalog to Raster Dataset tool to mosaic the rasters in the unmanaged raster catalog into a single raster dataset.

 

 

We conducted a similar test using GRID data and it yielded the following results:

Mosaic Test 2
Type of data: single band data
Input format: GRID
Number of files: 60
Average file size: 5.7 MB
Output format: GRID

Old Workflow – 45 minutes              
Create Raster Dataset time: 1 second
      Workspace to Raster Dataset time: 45 minutes

New workflow – 4 minutes
     
Create Unmanaged Raster Catalog: 1 second
Raster to Geodatabase tool: 1 minute
Raster Catalog to Raster Dataset tool: 3 minutes

The new workflow is shown in model form in the following graphic:

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2 Comments

  1. ssalas says:

    You state “have had varying feedback on performance, especially when outputting to a file format.” Can you share any performance testing when the output is enterprise ArcSDE?

  2. simo3919 says:

    In post is in regards to previous question, “Can you share any performance testing when the output is enterprise ArcSDE?”.

    This new workflow was to make the previous mosaics workflow to a file (e.g. GRID, IMG, TIFF, etc) faster.

    ArcSDE was always performing reasonably via any of the previous workflows/tools. This workflow can also be used to create a mosaic in ArcSDE, however there will be little or no performance benefit, since SDE already does the mosaic in an efficient manner (e.g. partial pyramid updating and extent are already in cplace by the SDE geodatabase).

    Simon W.