About combining service definitions
Legacy: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 The image service definition (.ISDef) has been replaced by an improved geodatabase data model—the mosaic dataset—which can be published as an image service using the ArcGIS Server Image extension.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 may be cases where you want to create multiple image service definitions that contain the same raster datasets, but have different properties or use different processes. For example, you can publish two image services that are identical except for the compression for transmission, thereby allowing clients with low bandwidths to have the option to reduce the compression when necessary. Or you might have an image service definition with color imagery, but for a specific application, the imagery can only be rendered as panchromatic imagery. In this case, only the applied service process would be different. Other examples in which only the service processes would change include creating multiple image service definitions with different band combinations or computation of NDVI from an image service of multispectral imagery. Or you might want to provide raw elevation data for one set of applications, then provide the same data rendered as a hillshade for visualization.
The following should only be attempted by advanced users who have experience in creating and using different image service definitions and are confident in how to copy individual files within an image service definition folder.
It is possible to create totally independent and different image service definitions, but this could make the management of such image service definitions difficult due to the high redundancy.
An image service definition is fully defined by individual components. The image service definition (.ISDef) folder contains the following:
- An .ISDef XML file
- A service table that defines the geometry of the footprint of each raster dataset
- A seamline shape that defines the seamlines to be used while seamline mosaicking
- A boundary shapefile that defines the extent of the service
- The raster process definition (.RPDef) files that define each raster dataset and contain the details on how to process each raster and the metadata of raster datasets
ArcGIS Image Server allows an image service definition to reference the service table, seamline shape, boundary, or .RPDef files of another image service definition. These references can be defined within the Service Definition section on the Image Service Properties dialog box.
Duplicating an image service definition
You create multiple image service definitions from a single image service definition using the Save As option on the Image Service Definition Editor toolbar. This allows you to optionally link to the service table, seamlines, boundary, or raster datasets of the original image service definition.
Changing service tables
A service table can be changed to point to the footprint shapefile of another image service definition. It is assumed that the footprint shape being referenced is defined in the same spatial reference system as the current image service definition. The same service table will be shared by two different image service definitions, and making changes to the service table of one will affect the other. For example, if the image service definition is built and the pixel size ranges are changed, this will have an effect on both services.
Changing Raster Source fields
There are cases where an image service definition is nearly identical to another, but only certain raster datasets need to be excluded or processing of specific raster datasets should be different. This can be controlled by redefining the Raster Source field. For example, if an image service definition should be the same as another but exclude specific sets of raster datasets, you should
- Use standard ArcGIS features to create a new field (for example, RSRC2).
- Copy the content of the Raster Source field into this field.
- Set the Raster Source fields that should not be used to NULL.
- Change the Raster Source field in the service definition properties to the new field (RSRC2).
Similarly, if the processing for a specific raster dataset should be different within one image service definition, you can manually change the Raster Source field for the specific raster to point to a modified version of the raster process definition that has been copied and changed.
Changing the seamline shape
If two different services need to use the same seamline mosaic lines, the Seamline shape source can be defined to reference the other image service definition. If the seamlines exist as a separate file and contain the RasterID field required to link to the service table, the Seamline shape source can be redefined. If two image service definitions are similar except for the seamlines, you can create a new image service definition with the same properties as an existing one. On the Image Service Properties dialog box, set the service table to point to the footprint of the previously defined image service definition. They will be similar, except they will use different seamlines.
Changing the shape of the boundary
If two image service definitions need to have the same boundary, the boundary source for one can be modified to point to the boundary shapefile of the other.
If a service subset of another service needs to be created, you can create it by copying the service definition and setting the service table to point to the footprint of the previous service. The seamline should point to the seamline of the previous service. The two services will be the same, except the boundary can be defined separately.