CREATE RELEASE POINTS

Summary

Create Release Points creates release locations at a specified distance interval along the pipeline centerline route features on which you are performing release modeling. These release point features serve as the “starting point” for your subsequent plume transport and product fate simulations.

To learn more about the Liquids HCA Tool in general, please see Liquids HCA Tool Frequently Asked Questions.

To learn more about the structure of the Liquids HCA Tool project geodatabase, please see Liquids HCA Tool Data Dictionary.

Usage

All overland plume and hydrographic transport features generated in subsequent liquids HCA analysis steps are referenced to their parent release point feature, as are the intersection records of the product plume with HCA features. Ultimately, your final regulatory “could affect” segments are constructed from continuous sequences of release point features whose product transport plumes intersect one or more HCAs.

The release point features output from the tool include attribution from your underlying input pipeline centerline route features, including the unique route identifier and the measure distance along the route. Each release point feature includes its own unique identifier, constructed from the unique route ID and the sequence number of the release point feature along the underlying centerline route. The release point features output by this tool also include specific attribution from your Liquid HCA project geodatabase’s global inputs table. When you supply the optional input pipe segment layer, the output release point features include pipe diameter and wall thickness attribution from the underlying input pipe segment features, which is used to calculate internal pipe diameter for drain down calculations in the Calculate Draindown tool.

Create Release Points calculates the elevation of each release point using the Esri Summarize Elevation (Ready to Use) tool in the ArcGIS Pro Ready to Use toolbox. This tool is an ArcGIS Online geoprocessing service that uses ArcGIS Online’s cloud-hosted data and analysis capabilities. Because of this, you must have internet access when you run Create Release Points.

Input Project Database – This is the project file geodatabase you created with the Initialize Database The Liquids HCA Tool project geodatabase is intended to store all data inputs and outputs generated during the analysis process.
Input Route Features – Your input route features are sourced from the centerline route features you imported into the project geodatabase using the Initialize Database tool. The tool looks for the ROUTES feature class in your specified project geodatabase and automatically sets this parameter to that value if the ROUTES feature class is present in your project geodatabase. If you specified a different name for your copied centerline route features when you ran Initialize Database, you’ll need to select that feature class here. Note that the input route features must include populated ROUTE_ID, FROM_MEAS, and TO_MEAS columns.
Input Global Inputs Table – The global inputs table that you populated using either the Enter Global Input Data tool or the Import Global Input Data tool is sourced from your specified project geodatabase. The tool looks for the GLOBAL_INPUTS table in your specified project geodatabase and automatically sets this parameter to that value if the GLOBAL_INPUTS table is present in your project geodatabase. If you specified a different name for your global inputs table when you ran Enter Global Input Data or Import Global Input Data, you’ll need to select that table here. The global inputs table provides attribution used by other tools in the Liquids HCA Analysis workflow. Create Release Points utilizes the following data columns from the global inputs table:
- ROUTE_ID – The field that uniquely identifies your centerline route features. ROUTE_ID values are copied to your output release point features and are used to look up the appropriate data record for the route in the global inputs table.
- N_INT_DIAM – If you do not specify input pipe segment features, the nominal internal diameter value from the global inputs table is used to establish the internal diameter value for your release points. N_INT_DIAM values are copied to your release points on a route-by-route basis.
- OFRES_TIME – Data from this column in the global inputs table establishes the containment response time for overland flow plume transport. OFRES_TIME values are copied to your release points on a route-by-route basis. You may subsequently modify the overland flow response time for individual release points if you desire.
- HTRES_TIME – The nominal response time for the entire centerline route for an emergency response team to achieve containment of a hazardous liquids release that enters a waterway (minutes). The response time should not be the best response time, but rather a reasonable worst-case response time.

Please see Liquids HCA Tool Project Database Data Dictionary for a complete list of Global Inputs fields.

Release Point ID Prefix – Unique identifiers for release points are created by concatenating an (optional) prefix defined by this parameter with the unique route identifier and an ordinal point number, which increases monotonically from one in measure direction along the centerline route. Each element of the release point identifier is separated by an underscore character, ‘_’ (e.g., <your prefix>_<route ID>_<release point number>). The default release point prefix is based on your Windows username and is restricted to a length of five characters. Although the prefix is optional, G2-IS strongly recommends that you use one. The combination of route identifier and release point number is unique within a Liquids HCA project, but not across projects. Since Microsoft Azure users may share a Batch account and its associated Storage account, the use of release point prefixes helps ensure that different users don’t accidentally overwrite each other’s work in Azure. Similarly, a single user may simultaneously execute multiple Liquids HCA projects on the same Azure Batch account. Judicious application of release point prefixes again guards against accidental data overwrite on Azure.
Release Point Interval – Data from the SPL_PT_INT column in the global inputs table is used to establish the distance interval between each release point on a route-by-route basis. If that data is missing from the global inputs table, the value you enter here is used instead. In general, the release point interval should be small enough that you don’t have any major gaps between the overland plumes for adjacent release points. Under no circumstances should you specify a release point interval smaller than the horizontal resolution (cell size) of your digital elevation data. The default value for this parameter is 30 meters (~100 feet). Note that the ends of your input pipeline centerline route features will always be covered by a release point feature.
Input Pipe Segment Features – This is an optional parameter. The tool uses any pipe segment data that you provide to more accurately define internal pipe diameter for your centerline route features (which is used to calculate pipe volume in subsequent drain down calculations in the Calculate Draindown tool). For your input pipe segment features to be useful, they must contain the following attribution:
- Pipe Segment Route Identifier Field – Select a field that uniquely identifies the route feature underlying the pipe segment feature. These field values are used as foreign key values to properly locate pipe segment features on their underlying centerline route features. The values from your selected field are compared to the ORIGINAL_ROUTE_ID column values in the centerline routes feature class in the project geodatabase.
- Pipe Segment Begin Measure Field – Select a field that stores the starting measure values for your input pipe segment features.
- Pipe Segment End Measure Field – Select a field that stores the ending measure values for your input pipe segment features.
- Pipe Segment Diameter Field – Select a field that stores the actual outside pipe diameter values for your input pipe segment features. For 14-inch nominal pipe diameter and larger, the actual outside diameter of the pipe is equal to the nominal pipe diameter. For 12-inch nominal pipe diameter and smaller, nominal diameter is not equal to actual outside pipe diameter. For example, the actual outside diameter of 12-inch nominal diameter pipe is 12.75 inches. If you have an internal diameter field, you may use it here, but make sure to leave the wall thickness field parameter blank.
- Pipe Segment Wall Thickness Field – Select a field that stores pipe wall thickness values for your input pipe segment features.
- Output Pipe Segment Features – The tool copies your input pipe segment features to a feature class named, by default, PIPESEGMENTS in the output project. There is generally no reason to change the default name of this feature class.

Create Release Points calculates internal pipe diameter using the formula:

internal diameter = actual outside diameter – (2 * wall thickness)

In a typical liquids HCA analysis workflow, you’ll run Create Release Points after Enter Global Input Data or Import Global Input Data. The release point features output by this tool serve as a primary input into the Calculate Draindown tool, which you’ll usually run next in a typical liquids HCA analysis workflow.

For visual reference on Liquids HCA Tool execution order, see Liquids HCA Tool Process Flow Diagrams.

Syntax

CreateReleasePoints_ (in_workspace, in_route_features, in_global_inputs_table, out_ospointm_features, {point_id_prefix}, in_point_interval, {in_pipesegment_features}, {in_pipeseg_route_id_field}, {in_pipeseg_fm_field}, {in_pipeseg_tm_field}, {in_nom_diam_field}, {in_wall_thk_field}, {out_pipesegment_features}, {username}, {password})

Parameter	Explanation	Data Type
in_workspace	Dialog Reference Specify the input liquids HCA project geodatabase. There is no Python reference for this parameter.	Workspace
in_route_features	Dialog Reference Specify the input pipeline centerline route features on which to generate release points. There is no Python reference for this parameter.	Feature Layer
in_global_inputs_table	Dialog Reference Select the global inputs table from your input project geodatabase. There is no Python reference for this parameter.	Table View
out_ospointm_features	Dialog Reference Specify the name of the output release point feature class. There is no Python reference for this parameter.	String
point_id_prefix	Dialog Reference Specify the release point identifier prefix. There is no Python reference for this parameter.	String
in_point_interval	Dialog Reference Specify the release point interval (in meters) at which to space release point features along centerline route features. (Used only when the release point interval is missing from the global inputs table.) There is no Python reference for this parameter.	Linear Unit
in_pipesegment_features (Optional)	Dialog Reference Specify a pipe segment feature layer for use in defining pipe diameter and wall thickness for your output release point features. There is no Python reference for this parameter.	Table View
in_pipeseg_route_id_field (Optional)	Dialog Reference Select the route identifier field that uniquely identifies the route features underlying the input pipe segment features. There is no Python reference for this parameter.	Field
in_pipeseg_fm_field (Optional)	Dialog Reference Select the field containing the starting measure value of your input pipe segment features. There is no Python reference for this parameter.	Field
in_pipeseg_tm_field (Optional)	Dialog Reference Select the field containing the ending measure value of your input pipe segment features. There is no Python reference for this parameter.	Field
in_nom_diam_field (Optional)	Dialog Reference Select an appropriate outside diameter field for your input pipe segment features. There is no Python reference for this parameter.	Field
in_wall_thk_field (Optional)	Dialog Reference Select the wall thickness field for your input pipe segment features. There is no Python reference for this parameter.	Field
out_pipesegment_features (Optional)	Dialog Reference Specify the output destination feature class for the copied input pipe segment features. There is no Python reference for this parameter.	Feature Layer
username (Optional)	Dialog Reference There is no dialog reference for this parameter. Python Reference Enter the username for your Enterprise Esri account when using the tool in Python scripting.	String
password (Optional)	Dialog Reference There is no dialog reference for this parameter. Python Reference Enter the password for your Enterprise Esri account when using the tool in Python scripting.	String Hidden

Code sample

The following script demonstrates how to use the Create Release Points tool with file geodatabase data:

import arcpy

arcpy.ImportToolbox(r”C:\Program Files\ArcGIS\Pro\bin\Python\envs\arcgispro-py3\Lib\site-packages\liquidshca\esri\toolboxes\LiquidsHCA.pyt”)

arcpy.env.workspace = r”C:\data\test.gdb”

in_workspace = r “C:\data\test.gdb”

route_features = r “C:\data\test.gdb\ROUTES”

global_inputs = r “C:\data\test.gdb\GLOBAL_INPUTS”

out_release_points = r “C:\data\test.gdb\OSPPOINTM”

point_interval = “30 Meters”

pipe_seg_layer = “Pipe_Segments”

pipe_seg_route_id = “Route_Id”

pipe_seg_from_meas = “From_Meas”

pipe_seg_to_meas = “To_Meas”

pipe_seg_daim = “Nom_Dia”

pipe_seg_wall_thk = “Nom_W_T”

out_pipe_segments = r “C:\data\test.gdb\PIPESEGMENTS”

username = “test”

password = “********”

arcpy.liquidshca.CreateReleasePoints(in_workspace, route_features, global_inputs, out_release_points, point_interval, pipe_seg_layer, pipe_seg_route_id, pipe_seg_from_meas, pipe_seg_to_meas, pipe_seg_daim, pipe_seg_wall_thk, out_pipe_segments, username, password)

Environments

Current Workspace, Scratch Workspace, Default Output Z Value, M Resolution, M Tolerance, Output M Domain, Output XY Domain, Output Z Domain, Output Coordinate System, Extent, Geographic Transformations, Output has M values, Output has Z values, XY Resolution, XY Tolerance, Z Resolution, Z Tolerance

Licensing information

This tool requires a valid Liquids HCA Tool user license or subscription. Please see the Request License and Register License tool help topics for details on obtaining and registering a Gas HCA Tool software license.

Credits

Use limitations

There are no access and use limitations for this item.