With the release of ArcGIS 10.X, the stand-alone ArcGIS Image Server product has been replaced with the ArcGIS Image Extension for Server. The ArcGIS Image Extension can be optionally licensed with the ArcGIS for Server Standard or Advanced editions.
There are significant differences in how the ArcGIS Image Extension is best implemented, and this post will provide some tips on how you can best take advantage of the new product.
One of the biggest changes that have been brought about with the ArcGIS Image Extension for Server is the use of mosaic datasets, a new data model in the geodatabase for managing collections of raster images. There are huge advantages to mosaic datasets, including the enablement of dynamic mosaicking to handle your overlapping images, and on-the-fly image processing where a variety of image functions can be applied on the server as the imagery is delivered to the user.
Mosaic datasets are created and edited with ArcGIS Desktop and published using ArcGIS Server with the Image Extension. Existing ISDef files can be added to mosaic datasets for conversion.
Mosaic datasets come in two varieties, one of which references imagery stored in the geodatabase, and the other that is used to reference imagery stored on a file server. This post discusses implementation of the second variety, which is known as a referenced mosaic dataset.
The following steps outline the configuration of a referenced mosaic dataset and the image service itself for the ArcGIS Image Extension for Server.
First, you must create a raster catalog in a file geodatabase on the server where the images are stored. Follow the steps for the Create Raster Catalog tool, and make sure to specify the proper spatial reference. You must select the folder that contains the imagery. In ArcCatalog, create the new file geodatabase by right-clicking on your folder connection and selecting New -> file geodatabase.
Next, create a new raster catalog in the new file geodatabase by right-clicking on the geodatabase name and selecting New -> Raster Catalog. Name the raster catalog and set the spatial reference. Make sure to set the Raster Management Type to “Unmanaged”.
Add images to the raster catalog using the Workspace to Raster Catalog tool. Make sure to set the coordinate system in the Environments settings for the tool. This process will take a few minutes to complete. When it finishes, check the list of raster files that were added to the raster catalog in ArcCatalog’s Preview tool.
Build pyramid layers for the new image files with the Batch Build Pyramids tool. Add raster files to the input list by selecting them from the ArcCatalog Contents window with the new raster dataset selected in the ArcCatalog tree. Copying the selected list of raster files into the tool’s input list will take a while.
For a new set of images, the default settings for most of the parameters are OK, but you will want to specify how many pyramid layers you want to build. The default is -1, which means to create the maximum number (29) of pyramid layers. Depending on how many images you are processing and how many pyramid layers you are creating for those images, this process can take a very long time.
If you want to check on the progress of the pyramid layer processing, you can go to the Results tab of ArcCatalog and see what image is being processed.
Next, create the referenced mosaic dataset (references the images from the file server and does not store them in the geodatabase), using the Create Referenced Mosaic Dataset tool. Follow the steps for the Create Referenced Mosaic Dataset tool selecting the raster catalog created earlier, and make sure to specify the proper spatial reference. Create the referenced mosaic dataset as the SDE table owner. Set privileges on the mosaic dataset, and then register the folder containing the imagery and the raster catalog with ArcGIS Server.
Test your results for the referenced mosaic dataset. Until you zoom in, the image service will only show you a maximum of 20 rater datasets.
Next, create the image service for ArcGIS Image Extension for Server to display. You can do this by right-clicking on the mosaic dataset name in ArcCatalog and selecting the Share as Image Service tool.
In the image Service Editor, analyze and resolve any errors and high priority warnings.
Preview the Image Service. Make sure that the images displayed show pixels at the native image resolution when you zoom all the way in.
Publish the image service by clicking the Publish button on the Service Editor dialog. This should not take more than a few minutes. You can also publish a map service by adding the referenced mosaic dataset to ArcMap and publishing the MXD file as a map service to the ArcGIS Server connection.
That’s it!
Anonymous says:
A basic mosaic dataset is the replacement for a raster catalog. You would create an empty mosaic dataset and then add source rasters. You could then publish the mosaic dataset through the Image Server Extension. A reference mosaic dataset is used to build derivative products from other mosaic datasets or an existing raster catalog. For example, you could build a reference mosaic dataset from mosaic datasets of aerial photos from different years and display the latest available imagery at any location. Another example would be creating a hillshade from a DEM by building a reference mosaic dataset of the DEM and applying a hillshade function to it. They help you build multiple image products by using mosaic datasets and raster catalogs as raster sources.
Scot Twining says:
Thanks for your comment Anonymous. You are correct in saying that a basic mosaic dataset is the replacement for a raster catalog. The referenced mosaic dataset was used in this case, so that the rater catalog could be used along with the Workspace to Raster Catalog command to collect all of the file names of the images stored on the file server. The Add Rasters to Mosaic Dataset tool can definitely be used to skip the raster catalog step, and several of the other steps. That is a great way to do this process, if you want to run all of the processes in succession without checking the results of each step as you go. With the length of time each of the longer processes takes, we chose to verify and test the output of each step before moving onto the next one. For instance, rather than creating 29 pyramid layers, we determined what the best number of pyramid layers was iteratively. Rather that calculating and storing 29 pyramid layers, we found that 10 was plenty. Lastly, the target audience for this article are our clients who have not yet upgraded from ArcGIS Image Server. Those people could choose to create their referenced mosaic dataset directly from an existing raster catalog if they wanted to. Thanks again for your comment.