Map Viewer now supports exporting and saving Group layers as layer items in ArcGIS Online. Group layers have been an essential part of maps and scenes in ArcMap and ArcGIS Pro. Support for Group layers was added to Map Viewer in 2020.
What Is a Group Layer?
Group layers are things that should remain together because they are conceptually related or meant to work together in a coordinated way. The ability to save an entire Group as a single item and share it as one item is a real time-saver for authors. It ensures multilayer, complex maps get imported by others correctly.
For example, a map might have five feature layers with a specific stacking order and with different blend modes applied to each layer to achieve a specific look. When saved as a Group layer item, the order and all settings are preserved. Settings don’t have to be manually recreated as they normally would if layers were just imported individually. When sharing multiple individual layers as a Group layer item, there is no need to provide instructions that explain how layers fit together. You can just share this single stack of layers as a Group item, and they are already wired up correctly.
Group layers are also great for adding structure to the table of contents by keeping things organized, much like folders on a desktop keep related things together. With Group layers, you can easily change the drawing order in the Contents pane by moving an entire Group layer.
In June 2023, the standard layer visibility controls for a Group layer were expanded in Map Viewer. By default, you can use a Group layer to turn all layer visibility within the Group on or off with the parent Group. You can set the visibility within a Group to exclusive visibility, which sets the visibility of the sublayers to only allow one sublayer on at a time. This control over layer visibility is supported by the Group layer item.
How to Create a Group Layer
To create a Group layer in your web map, click on a layer in the map and choose the Group option. Add more layers to the Group layer by dragging them into the Group layer. You can also use the option action to move the layer into an existing Group. This makes placing a layer into a Group easy, especially when dealing with nested Groups.
Adding Group Layer Items to Maps and Apps
Map Viewer allows you to add Group layers to maps in a variety of ways. You can add Group layers through the item details page and via the item browser. The new Atlas app will also support Group layers in its Add content workflows.
How to Save and Share a Group Layer Item
Once layers have been added to a Group layer, you can click on the options of the Group again and click Save As. This will create a Group layer item with layers.
This follows the same workflow as other supported layer item saving in Map Viewer. Enter in a title, tags, and folder placement.
To share the Group layer item, go to the Properties panel and under Info you will see the Layer Item button, which will open the Group layer item details page. Click Share and set sharing for the Group layer. This will review the layers within the Group and notify you if any layers in the Group layer item need to have their sharing settings updated.
Use Cases for Saving Group Layers
Whenever a map made from multiple layers is shared, it’s often very important that all those layers stay bundled so that they will be presented in the correct order with blend modes applied to the right layers. Also, layers with coordinated multiscale behaviors won’t be affected. Saving Group layers and sharing them as single items makes the chance of misplacing layers go down and productivity go up.
Example 1: Where There’s Smoke, There’s Fire
Esri offers many interesting live data streams, including satellite monitoring of wildfires. When combined with data from real-time smoke and haze monitoring, these two data streams show how the places most impacted by smoke can be hundreds or even thousands of miles downwind from a fire’s location.
The real-time smoke and haze monitoring layers are related, and keeping them together is a good use of Group layers. In addition, these layers use a mix of blending and map effects to create a glowing, hazy look, which is preserved when these layers are saved as a Group layer. See these layers at work.
Example 2: Trimming Media Layers with Sketch Masks
One of the cooler ways to use sketch drawing tools is as an invisible mask to show or hide parts of other layers in the map. For example, when scanned paper maps are used as georeferenced media layers, you may want to trim away parts of the original print map such as the title or border. Unneeded parts can be masked by a rectangle drawn in on a sketch layer. Since the image, masking, and blend modes all need to be used together as a single item to make the mask invisible, this is a perfect use case for Group layers. See how a sketch layer can be used with a media layer work together in this map. Learn more about how this was done by reading “Apply Cartographic Effects to Blend Media Layers into Maps.”
Example 3: Coordinated Multiscale Layers
The ability of web maps to reveal more details as readers zoom in is one of the most useful and expected capabilities in web maps. The way to author a coordinated multiscale map is to first author multiple feature layers that have been optimized and generalized for different spatial scales (e.g., global, continental, and country levels). Then define the visible range for each layer so that as the reader zooms in, layers turn on and off at a scale-appropriate time in a coordinated fashion. The easiest way to keep these layers bundled together is by saving them as a Group layer. And when the Group layer is saved, its characteristics are preserved without any additional work. This Group layer item shows American Community Survey (ACS) data on race and Hispanic origin variables at three different scales.
Next Steps
The next time you need to share a collection of map layers, be sure to use Group layers to organize and export them to preserve the relationship between layers. Additional enhancements are planned that will include support for Group layer items saved from 3D Scenes and support for opening and creating Group layer items in ArcGIS Pro. There will also be a growing collection of Group layer items in ArcGIS Living Atlas of the World, which is a great place to start learning more about what Group layers can do for you.
About the authors
Russell Roberts
