Image service layer properties
Layer properties for most image service
The image service layer has layer properties similar to other layers in ArcGIS. Like a raster dataset layer, the Layer Properties dialog box contains the General, Source, Extent, Display, and Symbology tabs. The General, Source, Extent, and Symbology tabs are similar to those for the raster dataset layer and other layers; however, the Display tab has one or two additional options.
The options on the Display tab include
- A check box to allow interactive display when using the Effects toolbar. If checked, the Effects toolbar allows you to interactively adjust the brightness or contrast of a layer. This option controls how the layer behaves if you use the Effects toolbar to modify contrast, brightness, or transparency. If unchecked, the layer will be updated only when you complete using the controls on the Effects toolbar.
- A check box to display the service resolution in the table of contents. The service resolution is the ratio of screen pixels to image cells at the current map scale. It helps you determine if you are close to displaying the maximum resolution of the raster.
- A drop-down menu that allows you to choose which resampling method will be used on the imagery that is displayed. The options include nearest neighbor, bilinear interpolation, cubic convolution, and majority.
- Text boxes allowing you to specify the percentages used for contrast, brightness, and transparency of the layer.
- Contrast—Specifies the contrast percentage for the layer. The default and neutral contrast is 0 percent. You can type any value between 100 and -100.
- Brightness—Specifies the brightness percentage to be used for the layer. The default normal brightness is 0 percent. You can type any value between 100 and -100.
- Transparency—Specifies the transparency percentage for the layer. This enables you to see the underlying layers. Type any value between 0 and 100 percent. Type 0 if you do not want any transparency.
- A drop-down menu and text box to specify the compression applied to transmitted data. This transmission compression can be preset in the source to an image service, but you can always change this. A highly compressed image is transmitted faster than an uncompressed image; however, the image quality may not be as good.
- None—No compression is applied to the imagery, which provides the highest quality but results in the maximum volume of data transfer across the network.
- LZ77—An efficient lossless compression method that is primarily for imagery with similar cells, such as scanned maps or results of classifications.
- JPEG—An efficient compression method that can often compress imagery by about three to eight times with little degradation of the image quality. When choosing the JPEG method, you can also edit the quality by typing a value from 0 to 100.
- A check box to allow viewing the footprints for each raster dataset in the image service and a symbol selector button to allow changing the symbology. Optionally, you can choose to only view the primary rasters, therefore, service overview footprints will not be displayed. (This is only available when the source to the image service is a mosaic dataset.)
The Symbology tab is similar to the raster dataset layer, but you will only have the option to change the renderer using the RGB or Stretched renderers. You can change the renderer, change the stretch applied to the histogram, and alter the background color and NoData representation.
Additional layer properties for the mosaic dataset source
When the image service is created from a mosaic dataset (not a single raster dataset), additional layer properties are presented on several other tabs, including the Mosaic, Selection, Fields, Definition Query, Status, and Time tabs.
The Mosaic tab is available when the source of an image service is a mosaic dataset (not a single raster dataset). The mosaicked image displayed from an image service can be created from a number of input rasters. The mosaic method defines how the mosaic is created from different rasters, such as By Attribute where a field containing values is use to sort the images, or Closest to Center, where the image closest to the center of the display is on top. The mosaic operator allows you to define how to resolve the overlapping cells, such as choosing a blending operation.
The available mosaic methods are defined as part of the image service properties and may not all appear to the client. The mosaic methods include
- Closest to Center—Enables rasters to be sorted based on a default order where rasters that have their centers closest to the view center are placed on top.
- Closest to Nadir—Enables rasters to be sorted by the distance between the nadir position and view center. This is similar to the Closest to Center method but uses the nadir point to a raster, which may be different than the center, especially for oblique imagery.
- Closest to Viewpoint—Orders rasters based on a user-defined location and nadir location for the rasters using the Viewpoint tool.
- By Attribute—Enables raster ordering based on a defined metadata attribute and its difference from a base value.
- North-West—Enables raster ordering in a view-independent way, where rasters with their centers to the northwest are displayed on top.
- Seamline—Cuts the raster using the predefined seamline shape for each raster using optional feathering along the seams and orders images based on the SOrder field in the attribute table.
- Lock Raster—Enables a user to lock the display of a single or multiple rasters based on the ObjectID.
- None—Orders rasters based on the order (ObjectID) in the mosaic dataset attribute table.
The mosaic operators include
- First—The overlapping areas will contain the cells from the first raster dataset listed in the source.
- Last—The overlapping areas will contain the cells from the last raster dataset listed in the source.
- Min—The overlapping areas will contain the minimum cell values from all the overlapping cells.
- Max—The overlapping areas will contain the maximum cell values from all the overlapping cells.
- Mean—The overlapping areas will contain the mean cell values from all the overlapping cells.
- Blend—The overlapping areas will be a blend of the cell values that overlap; this blend value relies on an algorithm that is weight based and dependent on the distance from the cells to the edge within the overlapping area.
The Selection tab allows you to alter how the footprint features will appear when selected.
The Fields tab displays the attribute fields that are transmitted with the image service. This tab is present when the image service contains multiple images and fields that can be queried. You can modify the fields by defining an alias for the field name. You can also choose to not display fields or to reorder how they will appear in the attribute table.
Definition Query tab
The Definition Query tab allows you to build a query to define a subset of a raster dataset that will be displayed in the image service. This tab is present when the image service contains multiple images and fields that can be queried. You can use Query Builder to build a query using a Structured Query Language (SQL) expression.
The Status tab allows you to examine the specific information about the image returned by the image service. This information includes the extent, the number of rows and columns of the image, the number of bands, a bit depth, and the size of the transmitted data. This tab is present when the image service contains multiple images.
If time can be enabled on this image service, you can enable it from this tab.
Additional layer properties for the image service definition source
Image service definitions are created with ArcGIS Image Server and are used to create image services using collections of raster data. These have been superseded by the mosaic dataset, starting with ArcGIS 10. However, many of them still exist and have a slightly different set of layer properties.
The properties on the Mosaic tab are nearly identical to those listed above.
Metadata and image properties are provided to every client application with an image service. Some default metadata information is dependent on the particular client application, and some metadata is transmitted at the discretion of the image service administrator.
There are two radio buttons, Source Rasters and Service Process. When you click the Source Rasters radio button, you can view the properties of each raster in the current display view and scale. Using the drop-down arrow, you can view the metadata for each individual raster or click the Lock button to lock the display to that individual raster.
When you click the Service Process radio button, you can view any processes applied on all the contents in the image service. If there are no processes applied to the image service, no process metadata will be transmitted and it will be blank. Also, if the administrator has chosen not to transmit the service process metadata, this will be blank.
This tab displays the current status and information about the image displayed in the application.
Number of rows of pixels
Number of columns of pixels
Data: Number Of Bands
Number of bands of the data
Data: Pixel Type
Type of the pixels
Data: Pixel Depth
Number of bits of the data
Data: Color Space
Color space of the data
Compression: Transmitted Size
The size of the image data in kilobytes transmitted to the client application
Compression: Compression Factor
The factor by which the image data is compressed before transmitting to the client application
Any kind of error on the part of the service provider—general failures, error in image service display, and so on