Map image layers can be used as layers in maps and scenes. Following are some common tasks for working with map image layers.
View map image layers in the Contents pane
Map image layers are added to the Contents pane as composite layers. You can expand a map image layer to see its sublayers. However, you cannot add or remove sublayers in the map image layer in the Contents pane. Since the layer is based on a map, you will see the layer organization in the source map. This order can't be changed. For example, you cannot insert a layer within this composite layer or divide the map image layer into its constituent sublayers.
Get information about a map image layer
In the layer's properties, the Source tab displays information such as the map extent, data (service) type, server name or URL, operations allowed and service restrictions, and the native coordinate system of the service.
Map image layer attributions
The data source credits or attributions for an ArcGIS Server map image layer are available to display in your printed or exported map. When you work with the layer in a map view, an icon located in the lower right corner of the map is available.
Clicking this icon opens a separate window that lists source information for all web layers currently turned on in your map. Once you export the map or create a layout, the icon is replaced with the text of the web layer attributions. You cannot move or change this text.
Change the display of map image layers
The Display tab in the layer's properties allows you to change the following:
- The background color
- The layer or color transparency for the web layer
- The image format used for delivering map service displays
Choose a background
All image-based services have a background. The background is any part of the image layer in which no map features are drawn. If the image type received from the server supports transparency, AllSource makes the background transparent by default. A transparent background is particularly useful for using the layer in mashups (such as for point and line web layers).
You can choose a different background by clicking the color picker and choosing a color for the background.
Set a color to be transparent
You can also set a specific color in the service as transparent. The following graphic shows a web layer. Since no transparency has been applied, you cannot see any layers under the states.
In the next graphic, the yellow used as the fill color (above) for the states is made the transparent color. The gray outlines are retained for each state, but you can now see the relief under the states layer.
Transparent color options are not available if the service does not provide image types that support transparency. If you apply No Color to the background, you do not make the background transparent, but rather make the background white. The background of a map image layer always has a color.
Set layer transparency
Adding transparency allows you to see map features under the layer. This adds information to your map and can add depth to your cartography. You can only add transparency to the layer, not to sublayers.
Change the web layer's image format
Many web layers can be served in a selected image format. By default, AllSource requests images in PNG 32. This format returns a high-quality image and supports transparency. However, its data size can be much larger than other formats. You can use smaller-sized formats, such as JPEG; however, layer transparency is not supported for JPEG.
To choose an available image format, use the Layer Image Format drop-down menu. This menu displays the format options supported by the service.
Save a web layer
When you save the map or scene containing a web layer or a layer file, the web layer connection information and the state of the web layer are saved as part of your map or scene. When you reopen the map, AllSource automatically reconnects to the server and sends an appropriate request based on the initial spatial reference, map extent, and saved state of your map layers. For example, if you turn off the visibility for a particular server layer (or its sublayers) and save the map, the layer remains turned off the next time you open the map.