Creating an image service containing other image services
ArcGIS 10 is the last release of the stand-alone ArcGIS Image Server product. The image service definition (.ISDef) has been replaced by an improved geodatabase data model—the mosaic dataset—which can be published as an image service using the ArcGIS Server Image extension.
There are a number of reasons for creating an image service definition that uses a published image service as its source imagery. For example, you may want to combine different image products to create another image product, as in
- Combining a hillshaded DEM with a topo map—This defines the workflow for creating a hillshaded topo map image service using two image service as the input to create the third image service.
- About the Pan-sharpen process—There is a workflow that describes using a three-band color image service and combining it with a higher-resolution, one-band grayscale image service to create a third image service, where the lower-resolution, color image service is sharpened by imagery from the higher-resolution image service.
- Using the Ortho process—You'll see that an image service can be used as the source for the DEM. This allows you to manage the elevation data separately from the imagery that is being orthorectified.
Image service definitions also have a limited file size, because they are built on the shapefile data structure. Each of the component files of a shapefile is limited to 2.14 GB; therefore, the .dbf and .shp files cannot exceed this size. This impacts users that need to add massive numbers of images to an image service definition, because each image is represented by one polygon in the shapefile. There are two ways to work around this limitation. If your data is uniform and tiled, like the USGS digital orthophoto quadrangles (DOQs), you can use a tiled raster dataset, so a group of tiles is only represented by a single polygon. See Adding tiled raster types to learn more about this solution. If your data isn't tile or the tiled raster type is not a solution you can use, the alternative is to create image service definitions containing subsets of your data so as to not exceed the approximate 2 GB shapefile limitation, then create another image service definition containing each of these subset image services.
- Create an image service definition.
- Publish the compiled image service definition.
- Open the image service in ArcMap or the Image Server Viewer.
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Save it as an image service reference file (.ISRef).
Create, publish, open, and save each image service you want to add to the final image service definition.
- Create the final image service definition, using the Direct Image Server Connection raster type to add the .ISRef files. See Adding georeferenced raster types.
- Publish this image service definition as you would any other.
Each image service referenced in the final image service must remain published; otherwise, the connection to them as source imagery will be lost, and the imagery will not be visible.