Working with Network Analysis Layers
Included in this tutorial:
What are Analysis Layers and sublayers?
Using Analysis Layers in ArcGIS Pro, including the basic workflow of network analysis
Tutorial Data: The tutorial includes demonstration with the Network Tutorial Data available here.
Credits: L. Meisterlin (2022)
This tutorial discusses the approach to network analysis employed by ArcGIS software–specifically, using “analysis layers.”
What is an Analysis Layer?
Unlike other geoprocessing operations, which are mostly accomplished through standalone tools, network analysis operations in ArcGIS are designed through an analysis layer. Much like mapping and data layers, an analysis layer will appear in the Contents panel of the interface.
Any features associated with the analysis will be contained within the layer as sublayers.
Service Area analysis layer
Closest Facility analysis layer
Route analysis layer
What are the Analysis Layer’s Sublayers?
The sublayers of an analysis layer include the inputs and the outputs of the analysis.
All network analysis layers include sublayers for optional barrier inputs. The required input sublayers and the generated output sublayers vary by analysis type.
For example (referring to the images above):
A service area analysis inputs include the facility locations to or from which service areas are calculate. The output options include any polygons or lines that are generated by the analysis once it is executed. (In the screenshot above, we can see that polygon service areas were created and are symbolized with colors representing their “cutoff” values or distance from the input facility.
A closest facility analysis inputs include both facility locations and incident locations. The analysis models routes to or from incidents while calculating the closest facility to each. These output route lines are included within the analysis as a sublayer.
A route analysis inputs include the location of stops (which, by default, are symbolized with numbers representing their order) through which a route will be calculated. Like the closest facility analysis, these route lines are included within the analysis as a sublayer.
Using Analysis Layers
the tools of the basic workflow
While there are specific tutorials for each of the tools required for using network analysis layers, it helps to understand the basic sequence and logic of working with layers to contain and execute analyses.
The tools for working with analysis layers are collected in the Network Analyst Tools > Analysis toolset. For your reference, the most commonly accessed tools for beginning to work with network analysis in ArcGIS are highlighted.
Unsurprisingly, all network analysis layers are associated with a specific network dataset. If you have not built the network dataset, you will need to before using an analysis layer. See Creating & Building a Simple Esri Network Dataset.
the basic workflow
First we must make an analysis layer (depending on the type of analysis you want to conduct). See, for example, Making a Service Area Analysis Layer. This will generate the layer visible in your Contents panel, as shown with the three example layers above. The new analysis layer will have empty sublayers.
Next we add locations to the input sublayers. As we saw above, the specific inputs vary by analysis type. That said, there is only one tool (called “Add Locations”) for this. With the tool, you can add locations to any input sublayer in a network analysis layer. See Adding Locations to a Network Analysis Layer.
Then, we solve the analysis layer. “Solving” will execute the analysis based on the parameters of the analysis layer and the input locations, then it will add the results to the appropriate output sublayer within the overall analysis layer. (Notice, again, the outputs listed under the “Polygons” sublayer in the service area example above.) Outputs are temporary. See Solving a Network Analysis Layer.
Examine results. If necessary: Make changes to the analysis layer’s parameters and properties. Add new or different locations. Solve again.
When you are satisfied with your outputs, export the sublayer as feature classes (as you would export any other layer), by right-clicking on their name in the Contents panel and clicking through Data > Export Features.