Image services and their capabilities

An image service provides access to raster (and image) data through a Web service. The source of the raster data can be a raster dataset (from a geodatabase or file on disk), a mosaic dataset, or a layer file referencing a raster dataset or mosaic dataset. Publishing a mosaic dataset as an image service requires the ArcGIS Server Image Extension. Once you publish the raster data to your server, you can use the resulting image service in ArcGIS Desktop the same way you would add any other GIS service layer.

Legacy:

You can also publish compiled image service definition (*.ISCDef) files created using ArcGIS Image Server. To do this, you must register ArcGIS Image Server with ArcGIS Server.

Learn about registering ArcGIS Image Server with ArcGIS Server

Image service capabilities

When you publish an image service, the default Image Service capability is always enabled. You can also choose to enable it with Open Geospatial Consortium, Inc., WMS or WCS capabilities. The different sources for an image service result in slightly different capabilities and affect the layer properties.

Image Service capabilities

An image service served with Image Service capabilities is designed for the GIS Web server architecture and is similar to the mapping capabilities of a map service. It can host any type of raster dataset or mosaic dataset or their layers. You can connect to these image services via the Add ArcGIS Server connection by entering a Universal Resource Locator (URL, such as an HTTP address) or by providing a LAN address, such as the name or IP address of a computer.

There are five operations that are available when using the Image Service capabilities. Each of these options can limit what users can do with your Web service.

Operation	Description
Image	Allows the image to be displayed. This is always active.
Catalog	Allows the client to open the table of a mosaic dataset when it is served.
Metadata	Allows the client to see metadata information for each raster when serving a mosaic dataset.
Download	Allows rasters to be downloaded when serving a mosaic dataset.
Pixels	Allows the API developer to access the pixel blocks of the individual rasters when serving a mosaic dataset.

Image Service operations

WCS capabilities

An image service served with the OGC WCS capabilities has many of the Image Service capabilities. You can enable the WCS capability on any type of image service, regardless of the raster data source type. You can connect to a WCS service via ArcGIS Desktop or third-party applications that support WCS. The layer properties of the WCS image services are the same as the default Image Service, but the raster is rendered on the client side, unlike the default Image Service, where the server renders the raster data. Therefore, the values transmitted are the raw data values; thus, the image service can be used as input for analysis or display. For example, a WCS image service layer can be used in a geoprocessing model or used to generate the surface in the ArcGlobe application.

WMS capabilities

An image service served with the OGC WMS capabilities has functionality similar to other WMS services. You can serve a raster dataset directly with WMS capabilities; you do not need to create a map document containing a raster dataset layer. An image service served as a WMS service contains only one layer, since it represents one input. You can connect to a WMS service in ArcGIS Desktop, through Web mapping applications, or using other applications that support WMS. When the raster data is served using WMS, it is rendered by the server and delivered to the consumer as a picture with coordinates. Users cannot change any of the properties of the data delivered via the WMS service. When publishing raster data using WMS, the image service is limited to grayscale or RGB color images, provided by rendering a single band (grayscale), a single band with a color map, or a three-band combination. By default, a raster dataset is served with the default layer settings (and band combinations). Additionally, the data is resampled to an eight-bit image.

Publishing the image service with the WMS capability allows you to use the service in ArcGIS Explorer or ArcGIS Server Web Mapping Applications, since both of these support WMS as a data source.