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Make Service Area Analysis Layer (Network Analyst Tools)

Summary

Makes a service area network analysis layer and sets its analysis properties. A service area analysis layer is useful in determining the area of accessibility within a given cutoff cost from a facility location. The layer can be created using a local network dataset or a routing service hosted online or in a portal.

Usage

  • This tool is typically used as the first step in a network analysis workflow. Once the layer is created, you can add inputs to it using the Add Locations tool and solve the analysis using the Solve tool.

    Learn more about the network analysis layer workflow

  • When ArcGIS Online or an ArcGIS Enterprise portal whose routing services are configured using ArcGIS Online is used as the input network data source, solving the analysis will consume credits and will be subject to certain limits, such as the number of allowed inputs.

    Learn more about credit consumption and analysis limits in network analysis

  • By default, the new analysis layer's data will be created in a new, automatically-named feature dataset in the Current Workspace geoprocessing environment, which is usually the project geodatabase. Table-based data will be created at the root level of the same geodatabase because tables cannot be stored in a feature dataset. You can override this behavior using the Analysis Geodatabase and Analysis Feature Dataset Name parameters.

  • Although this tool can be used in a Python script, the recommended best practice for performing network analysis in Python is to use the solver classes in the arcpy.nax module instead.

    Learn more about performing network analysis in Python.

Parameters

Label Explanation Data type

Network Data Source

The network dataset or service on which the network analysis will be performed.

The parameter can be specified using the following:

  • The catalog path to a network dataset.

  • A network dataset layer

  • The URL for ArcGIS Online or an ArcGIS Enterprise portal configured with standard routing services

To use a portal URL, you must be signed in to the portal with an account that has routing privileges.

Learn more about network analysis using routing services

When using ArcGIS Online or an ArcGIS Enterprise portal whose routing services are configured using ArcGIS Online as the input network, solving the analysis will consume credits and will be subject to certain limits, such as the number of allowed inputs.

Learn more about credit consumption and analysis limits in network analysis

Network Dataset Layer; String

Layer Name

(Optional)

The name of the network analysis layer that will be created.

String

Travel Mode

(Optional)

The name of the travel mode that will be used in the analysis. The travel mode represents a collection of network settings, such as travel restrictions and U-turn policies, that determine how a pedestrian, car, truck, or other medium of transportation moves through the network. Travel modes are defined on your network data source.

An arcpy.na.TravelMode object and a string containing the valid JSON representation of a travel mode can also be used as input to this parameter.

String

Travel Direction

(Optional)

Specifies the direction of travel to or from the facilities.

Using this parameter can result in different service areas on a network with one-way restrictions and different impedances based on direction of travel. The service area for a pizza delivery store, for example, should be created away from the facility, whereas the service area of a hospital should be created toward the facility.

  • Away from facilities—The direction of travel is away from the facilities. This is the default.

  • Toward facilities—The direction of travel is toward the facilities.

String

Cutoffs

(Optional)

The extent of the service area to be calculated in the units of the impedance attribute used by the selected travel mode. For example, when analyzing driving time, a cutoff value of 10 means that the resulting service area will represent the area reachable within a 10-minute drive time.

Multiple cutoffs can be set to create concentric service areas. For example, to find two-, three-, and five-minute service areas for the same facility, specify 2, 3, and 5 as the values for this parameter.

This default cutoff value can be overridden on a per-facility basis by specifying individual break values in the facilities sublayer.

Double

Time of Day

(Optional)

The time to depart from or arrive at the facilities of the service area layer. The interpretation of this value as a departure or arrival time depends on whether travel is away from or toward the facilities.

  • It represents the departure time if Travel Direction is set to Away from facilities.

  • It represents the arrival time if Travel Direction is set to Toward facilities.

This parameter is most useful for finding the roads that can be reached based on a travel mode that uses an impedance attribute that varies with the time of the day, such as one based on dynamic traffic conditions. Solving the same analysis using different values for this parameter allows you to see how a facility's reach changes over time. For example, the five-minute service area around a fire station may start out large in the early morning, diminish during the morning rush hour, grow in the late morning, and so on throughout the day.

A date and time can be specified as 10/21/2015 10:30 AM, for example.

Configure the analysis to use one of the following special dates to model a day of the week or the current date instead of a specific, static date:

  • Today—12/30/1899

  • Sunday—12/31/1899

  • Monday—1/1/1900

  • Tuesday—1/2/1900

  • Wednesday—1/3/1900

  • Thursday—1/4/1900

  • Friday—1/5/1900

  • Saturday—1/6/1900

Learn more about how dates and times are used and interpreted in a network analysis

Date

Time Zone

(Optional)

Specifies the time zone for the time of day parameter.

  • Local time at locations—The time of day parameter will use the time zone or zones in which the facilities are located. The start or end times of the service areas are staggered by time zone. This is the default.For example, setting time of day to 9:00 a.m. causes service areas to be generated for 9:00 a.m. eastern time for facilities in the eastern time zone, 9:00 a.m. central time for facilities in the central time zone, 9:00 a.m. mountain time for facilities in the mountain time zone, and so on. If stores in a chain that span the U.S. open at 9:00 a.m. local time, choose this parameter value to find market territories at opening time for all stores in one solve. First, the stores in the eastern time zone open and a polygon is generated. An hour later, stores open in the central time zone, and so on. Nine o'clock is always in local time but staggered in real time.

  • UTC—The time of day parameter will use coordinated universal time (UTC). All facilities are reached or departed from simultaneously, regardless of the time zone or zones in which they are located.Setting time of day to 2:00 p.m. causes service areas to be generated for 9:00 a.m. eastern standard time for facilities in the eastern time zone, 8:00 a.m. central standard time for facilities in the central time zone, 7:00 a.m. mountain standard time for facilities in the mountain time zone, and so on.

    Note:

    The scenario above assumes standard time. During daylight saving time, the eastern, central, and mountain times will each be one hour ahead (that is, 10:00, 9:00, and 8:00 a.m., respectively). One of the cases in which the UTC option is useful is to visualize emergency response coverage for a jurisdiction that is split into two time zones. The emergency vehicles are loaded as facilities. Time of day is set to now in UTC. (You need to determine what the current time and date are in terms of UTC to correctly use this option.) Other properties are set and the analysis is solved. Even though a time-zone boundary divides the vehicles, the results show areas that can be reached given current traffic conditions. This same process can be used for other times as well, not just for now.

String

Output Type

(Optional)

Specifies the type of output that will be generated. Service area output can be line features representing the roads reachable before the cutoffs are exceeded or the polygon features encompassing these lines (representing the reachable area).

The lines and polygons and lines output types are not available if the network data source is a service on a version of Portal for ArcGIS that does not support line generation.

  • Polygons—The service area output will contain polygons only. This is the default.

  • Lines—The service area output will contain lines only.

  • Polygons and lines—The service area output will contain both polygons and lines.

String

Polygon Detail

(Optional)

Specifies the level of detail of the output polygons.

If the analysis includes an urban area with a grid-like street network, the difference between generalized and standard polygons will be minimal. However, for mountain and rural roads, the standard and high precision polygons may present more accurate results than generalized polygons.

  • Standard—Polygons with a standard level of detail will be created. This is the default.

  • Generalized—Generalized polygons will be created using the network's hierarchy attribute to produce results quickly. This option is not available if the network does not have a hierarchy attribute.

  • High—Polygons with a higher level of detail will be created for applications in which precise results are important.

String

Geometry at Overlaps

(Optional)

Specifies the behavior of service-area output from multiple facilities in relation to one another.

  • Overlap—Individual polygons or sets of lines for each facility will be created. The polygons or lines can overlap each other. This is the default.

  • Dissolve—The polygons of multiple facilities that have the same cutoff value will be joined into a single polygon. This option does not apply to line output.

  • Split—An area will be assigned to the closest facility so polygons or lines do not overlap each other.

String

Geometry at Cutoffs

(Optional)

Specifies the behavior of service area output for a single facility when multiple cutoff values are specified. This parameter does not apply to line output.

  • Rings—Each polygon will include only the area between consecutive cutoff values. It will not include the area between the facility and any smaller cutoffs. For example, if you create 5- and 10-minute service areas, the 5-minute service area polygon will include the area reachable in 0 to 5 minutes, and the 10-minute service area polygon will include the area reachable in 5 to 10 minutes. This is the default.

  • Disks—Each polygon will include the area reachable from the facility up to the cutoff value, including the area reachable within smaller cutoff values. For example, if you create 5- and 10-minute service areas, the 10-minute service area polygon will include the area under the 5-minute service area polygon.

String

Polygon Trim Distance

(Optional)

The service area polygon trim distance. The polygon trim distance is the distance the service area polygon will extend from the road, similar to a line buffer size. It roughly models how far back from the road centerlines is considered reachable from the road.

This parameter includes a value and units for the distance. The default value is 100 meters.

The trim distance applies only in areas that are not fully surrounded by other reachable roads. Areas fully surrounded by reachable roads will be covered by the service area polygon regardless of the trim distance setting.

Tip:

To generate a polygon that includes only the area within the trim distance of reachable roads, configure the service area analysis to output lines instead of polygons and use the Buffer or Pairwise Buffer tool to create simple buffers.

Linear Unit

Exclude Sources From Polygon Generation

(Optional)

The network dataset edge sources that will be excluded when generating service area polygons. Polygons will not be generated around the excluded sources, even though they are traversed in the analysis.

Excluding a network source from service area polygons does not prevent those sources from being traversed. Excluding sources from service area polygons only influences the polygon shape of the service areas. To prevent traversal of a given network source, you must create an appropriate restriction when defining the network dataset.

This is useful if you have some network sources that you don't want to be included in the polygon generation because they create less-accurate polygons or are inconsequential for the service area analysis. For example, while creating a walk-time service area in a multimodal network that includes streets and metro lines, you should exclude the metro lines from polygon generation. Although the traveler can use the metro lines, they cannot stop partway along a metro line and enter a nearby building. Instead, they must travel the full length of the metro line, exit the metro system at a station, then use the streets to walk to the building. It would be inaccurate to generate a polygon feature around a metro line.

This parameter is not available when the output geometry types do not include polygons, there are fewer than two edge sources in the network, the network data source is an ArcGIS Online service, or the network data source is a service on a version of Portal for ArcGIS that does not support excluding sources.

String

Accumulate Attributes

(Optional)

A list of cost attributes to be accumulated during analysis. These accumulated attributes are for reference only; the solver only uses the cost attribute used by the designated travel mode when solving the analysis.

For each cost attribute that is accumulated, a Total_ [Impedance] property is populated in the network analysis output features.

This parameter is not available if the analysis layer is not configured to output lines, the network data source is an ArcGIS Online service, or the network data source is a service on a version of Portal for ArcGIS that does not support accumulation.

String

Ignore Invalid Locations at Solve Time

(Optional)

Specifies whether invalid input locations will be ignored. Typically, locations are invalid if they cannot be located on the network. When invalid locations are ignored, the solver will skip them and attempt to perform the analysis using the remaining locations.

  • Checked—Invalid input locations will be ignored and only valid locations will be used. This is the default.

  • Unchecked—All input locations will be used. Invalid locations will cause the analysis to fail.

Boolean

Analysis Geodatabase

(Optional)

The file geodatabase workspace where the new network analysis layer's sublayer data will be stored. When this parameter is not specified, the sublayer data will be created in the Current Workspace geoprocessing environment, which is usually the project geodatabase.

Learn more about the analysis data source of a network analysis layer

Workspace

Analysis Feature Dataset Name

(Optional)

The name to use for the new feature dataset that the tool will create in the analysis geodatabase to store the network analysis layer's sublayer data. When not specified, the feature dataset will be created with a random unique name.

Learn more about the analysis data source of a network analysis layer

String

Derived output

Label Explanation Data type

Network Analyst Layer

The newly created network analysis layer.

Network Analyst Layer

Environments

Current Workspace

Licensing information

  • Basic: Yes
  • Standard: Yes
  • Advanced: Yes