HCA (Method 1 – External Class Location Data)

Summary

HCA (Method 1 – External Class Location Data) performs a High Consequence Area (HCA) analysis workflow from start to finish using your own Class Location data, rather than that generated by the Gas HCA Tool. HCA (Method 1 – External Class Location Data) is implemented as a ModelBuilder model tool using the tools from the Prepare and Process toolsets in the Gas HCA Tool Python toolbox. It creates a Gas HCA Tool project geodatabase, imports Class Location records and additional required data from your pipeline database, performs data conditioning and intermediate calculations, and calculates HCA ranges by method 1 per 49 CFR §192.903(1)

Usage

HCA (Method 1 – External Class Location Data) implements G2-IS’ best practices for HCA method 1 analysis. However, because it is implemented as a ModelBuilder model tool, you are free to make a copy of the tool and modify it to suit your own needs.

The following tools are used within HCA (Method 1 – External Class Location Data). They are listed in their order of execution within the tool; the heading for each section below is a hyperlink to the detailed help for the tool. Please note that while the tools HCA (Method 1 – External Class Location Data) uses are listed in the order in which they are executed, the tool parameters are shown in association with the tools that expose them, not necessarily in the order in which HCA (Method 1 – External Class Location Data) lists them:

1) Initialize Database

Initialize Database tool creates a project file geodatabase for the HCA analysis. It stores copies of your input data (to preserve all data used in the analysis), as well as intermediate results and final HCA range outputs. The first and last parameters exposed by the HCA (Method 1 – External Class Location Data) tool are from Initialize Database.

  • Project Name – Your HCA analysis project is internally identified in the Gas HCA Tool project geodatabase by a Global Unique Identifier (GUID) value. Your designated project name serves as an informal, human-readable name for your analysis project.
  • Output Project Geodatabase Initialize Database creates a new file geodatabase to store the project data.

2) Copy Centerlines

Copy Centerlines copies your centerline features from your pipeline database into the CENTERLINE feature class in the project geodatabase. Note the tool assumes your input centerline features are the same as those used to calculate your input external Class Location features.

  • Input Centerline Features – Your input centerline features should consist of the continuous, non-branching runs of pipeupon which you desire to perform calculations.

Your input centerline features must contain the following attributes (your field names need not match, but fields containing this information must be present):

      • Centerline Identifier Field – A field that uniquely identifies each input centerline feature. Your centerline ID field is preserved in the ORIGINAL_ROUTE_ID field in the CENTERLINE feature class in the project geodatabase.
      • Centerline Begin Measure Field – A field that defines the begin measure values of your centerline features.
      • Centerline End Measure Field – A field that defines the end measure values of your centerline features.

3) Prepare Centerline Buffers

Prepare Centerline Buffers creates centerline Class Location unit width and qualifying area/building selection distance buffer features, as well as ‘dissolved’ versions of the same for use in display. The undissolved and dissolved versions of the output centerline buffer features are stored in the following feature classes in the project geodatabase: CENTERLINE_STRUCTURE_BUFFER, CENTERLINE_STRUCTURE_BUFFER_DISSOLVED, CENTERLINE_QUALIFIED_AREA_BUFFER and CENTERLINE_QUALIFIED_AREA_BUFFER_DISSOLVED.

  • Structure Buffer Distance – The default value of 660 feet represents the mandated Class Location unit width, per 49 CFR §192.5(a)(1). However, you should specify whatever Class Location unit width you used in calculating your external Class Location features.
  • Qualifying Area Buffer Distance– This parameter is analogous to the above Structure Buffer Distance parameter but applies instead to Class Location qualifying areas and buildings. The default value of 300 feet conforms to that specified by regulation. However, you should specify whatever qualifying area/building selection distance you used in calculating your external Class Location features.

4) Prepare Structures

Prepare Structures copies your point and/or polygon Building Intended for Human Occupancy (BIHO) features from your pipeline database into your project geodatabase for use in the analysis. The tool assumes you are importing the same BIHO features you used in calculating your external Class Location features. The output features are stored in the following feature classes in the project geodatabase: STRUCTURE_POINT and STRUCTURE_POLYGON.

  • Input Structures Features – This parameter allows you to select multiple input layers or feature classes, and to mix point and polygon shape types in the input feature layers or feature classes. However, all input layers/feature classes must have a common schema. Your input BIHO features must contain the following attributes (your field names need not match, but fields containing this information must be present):
      • Structure Identifier Field – A field that uniquely identifies each input BIHO feature. Your structure ID field is preserved in the ORIGINAL_STR_OR_AREA_ID field in the STRUCTURE_POINT and STRUCTURE_POLYGONfeature classes in the project geodatabase.
      • Number of Dwelling Units Field – This parameter indicates the number of dwelling units present in the BIHO feature. For a single-family residence, the number is 1. For an apartment structure, the number is the number of apartment units in the feature.
      • Number of Stories Field – This field contains the number of stories in the BIHO feature. This field is used in the determination of Class 4 ranges in Class Location analysis. This field is not used in HCA-MCA analysis.
      • Discovery Date Field for Structures – This optional field stores the date on which the BIHO feature was actually discovered in the field.
      • Database Date for Structures – This optional field stores the date on which the BIHO feature was entered into your pipeline database.

5) Prepare Qualifying Areas

Prepare Qualifying Areas tool copies your point or polygon features for identified sites from your pipeline database into your project geodatabase. The tool assumes you are importing the same identified site/qualifying area/building features you used in calculating your external Class Location results. The output features are stored in the following feature classes in the project geodatabase: QUALIFYING_AREA_POINT and QUALIFYING_AREA_POLYGON.

  • Input Identified Site Features – This parameter allows you to select multiple input layers or feature classes, and to mix point and polygon shape types in the input feature layers or feature classes. However, all input layers/feature classes must have a common schema. Your input identified site features must contain the following attributes (your field names need not match, but fields containing this information must be present):
      • Identified Site Identifier Field – A field that uniquely identifies each input identified site feature. Your identified site identifier field is preserved in the ORIGINAL_STR_OR_AREA_ID field in the QUALIFYING_AREA_POINT and QUALIFYING_AREA_POLYGON feature classes in the project geodatabase.
      • Identified Site Type Field – A field that defines the type of identified site. This field is intended primarily for use in map display; all features in the QUALIFYING_AREA_POINT and QUALIFYING_AREA_POLYGON feature classes are used in analysis.
      • Discovery Date Field for Identified Sites – This optional field stores the date on which the identified site feature was actually discovered in the field.
      • Database Date for Identified Sites – This optional field stores the date on which the identified site feature was entered into your pipeline database.

6) Prepare Pipe Segment and MAOP Features

Prepare Pipe Segment and MAOP Features copies your pipeline database pipe segment and Maximum Allowable Operating Pressure (MAOP) features (or records) to the PIPESEGMENT and MAOP tables, respectively in the project geodatabase.

  • Input Pipe Segment Features – Typically, your input pipe segment features/records correspond to discrete lengths of pipe with common attributes stored on your pipeline centerlines. Your input pipe segment features/records must contain the following attributes (your field names need not match, but fields containing this information must be present):
      • Pipe Segment Centerline Identifier Field – This field uniquely identifies the centerline feature on which the pipe segment feature/record occurs. This field will be mapped to and compared with ORIGNIAL_ROUTE_ID field in CENTERLINE feature class.
      • Pipe Segment Begin Measure Field – A field that represents the begin measure of the pipe segment.
      • Pipe Segment End Measure Field – A field that represents the end measure of the pipe segment.
      • Pipe Segment Outside Diameter Field – A field that represents the diameter of the pipe segment in inches.
  • Input MAOP Features – Typically, your input MAOP features/records correspond to centerline segments with common MAOP values. Your input MAOP features/records must contain the following attributes (your field names need not match, but fields containing this information must be present):
      • MAOP Centerline Identifier Field – This field uniquely identifies the centerline feature on which the MAOP feature/record occurs. This field will be mapped to and compared with ORIGNIAL_ROUTE_ID field in CENTERLINE feature class.
      • MAOP Begin Measure Field – A field that represents the begin measure of the MAOP segment.
      • MAOP End Measure Field – A field that represents the end measure of the MAOP segment.
      • MAOP Field – A field that the MAOP value (in PSI) of the segment.

7) Create Centerline PIR Buffers

Create Centerline PIR Buffers creates centerline Potential Impact Radius (PIR) segments on your centerline features, and then creates centerline PIR segment buffer polygons. The output features are stored in the following feature classes in the project geodatabase: HCA_PIR_SEGMENT and HCA_PIR_SEGMENT_BUFFER.

  • PIR Factor – The PIR combustion factor varies based on product type. 0.69, the factor for ‘dry’ natural gas, is the default value. 0.73 is the factor for ‘wet’ natural gas.
  • Additional PIR Tolerance (Feet) – This parameter enables you to specify an additional tolerance (in Feet) to add to the PIR, to account for uncertainty in the spatial location of your centerline, BIHO and identified site features.

8) Create Structures and Site PIR Buffers

Create Structure and Site PIR Buffers creates PIR buffer polygons on your BIHO and identified site features and then generates centerline PIR BIHO and identified site segments by intersecting the buffer polygons for BIHOs and identified sites with your centerline features. The output features are stored in the following feature classes in the project geodatabase: HCA_STRUCTUREBUFFER and HCA_STRUCTURESEGMENT.

HCA (Method 1 – External Class Location Data) exposes none of this tool’s parameters.

9) HCA Calculation (Method 1 – External Class Location Data)

HCA Calculation (Method 1 – External Class Location Data) performs the final step in the HCA analysis workflow. It imports your external Class Location data, and then determines HCA ranges by method 1. This tool also produces dynamically segmented HCA segments that retain much useful attributes from the analysis process. The imported Class Location data is output to the DOT_CLASS_RANGE_IMPORT table. The output HCA range and segment features are stored in the following feature classes in the project geodatabase: HCA_RANGE_M1, HCA_SEGMENT_COUNT_M1.

  • Input External Class Location Features – This tool uses as input your own Class Location features (or records) from your pipeline database and imports them into the project geodatabase. However, your input Class Location features/records must contain the following attributes for the tool to run:
      • External Class Location Centerline Identifier Field – A field that uniquely identifies the centerline feature on which each input Class Location feature/record occurs. This field will be mapped to and compared with ORIGINAL_ROUTE_ID field in the CENTERLINE feature class.
      • External Class Location Begin Measure Field – A field that defines the begin measure values of your Class Location features/records.
      • External Class Location End Measure Field – A field that defines the end measure values of your Class Location features/records.
      • External Class Location Class Field – A field that contains the class location values for your Class Location features/records.

Syntax

HCAMethod1DotClassFromOtherSources (Project_Name, Input_Centerline_Features, Centerline_Identifier_Field, Centerline_Begin_Measure_Field, Centerline_End_Measure_Field, Input_Structure_Features, Structure_Identifier_Field, Number_of_Dwelling_Units_Field, Number_of_Stories_Field, Structure_Buffer_Distance_Field, {Discovery_Date_Field_for_Structures}, {Database_Date_Field_for_Structures}, Input_Identified_Site_Features, Identified_Site_Identifier_Field,

Identified_Site_Type_Field, Identified_Site_Buffer_Distance, {Database_Date_Field_for_Identified_Sites}, {Discovery_Date_Field_for_Identified_Sites}, Input_Pipe_Segment_Features, Pipe_Segment_Centerline_Identifier_Field, Pipe_Segment_Begin_Measure_Field, Pipe_Segment_End_Measure_Field, Pipe_Segment_ Outside_Diameter_Field, Input_MAOP_Features, MAOP_Centerline_Identifier_Field, MAOP_Begin_Measure_Field, MAOP_End_Measure_Field,MAOP_Field, PIR_Factor, {Additional_Tolerance_for_PIR__Feet_}, Input_External_Class_Location_Features, External_Class_Location_Centerline_Identifier_Field, External_Class_Location_Begin_Measure_Field, External_Class_Location_End_Measure_Field, External_Class_Location_Class_Field, Output_Project_Geodatabase)

Parameter Explanation Data Type
Project_Name

Dialog Reference

Specify your project name.

There is no Python reference for this parameter.

String
Input_Centerline_Features

Dialog Reference

Specify your input centerline features.

There is no Python reference for this parameter.

Table View
Centerline_Identifier_Field

Dialog Reference

Select the field that uniquely identifies your input centerline features.

There is no Python reference for this parameter.

Field
Centerline_Begin_Measure_Field

Dialog Reference

Select the field that contains the begin measure values for your input centerline features.

There is no Python reference for this parameter.

Field
Centerline_End_Measure_Field

Dialog Reference

Select the field that contains the end measure values for your input centerline features.

There is no Python reference for this parameter.

Field
Input_Structures_Features

Dialog Reference

Specify your input BIHO features. You may select multiple point and polygon feature layers or feature classes.

There is no Python reference for this parameter.

Multiple Value
Structure_Identifier_Field

Dialog Reference

Select the field that uniquely identifies each BIHO feature.

There is no Python reference for this parameter.

String
Number_of_Dwelling_Units_Field

Dialog Reference

Select the field that defines the number of dwelling units in each BIHO feature.

There is no Python reference for this parameter.

String
Number_of_Stories_Field

Dialog Reference

Select the field that defines the number of stories in each BIHO feature.

There is no Python reference for this parameter.

String
Structure_Buffer_Distance_Feild

Dialog Reference

Specify the desired BIHO buffer selection distance value and linear units of measure. The default value is 660 feet.

There is no Python reference for this parameter.

Linear unit

Discovery_Date_Field_for_Structures

(Optional)

Dialog Reference

Specify the field that records the ‘discovery date’ of your BIHO features.

There is no Python reference for this parameter.

String

Database_Date_Field_for_Structures

(Optional)

Dialog Reference

Specify the field that records the date at which your BIHO features were added to your pipeline database.

There is no Python reference for this parameter.

String
Input_Identified_Site_Features

Dialog Reference

Specify your input identified site features. You may select multiple point and polygon feature layers or feature classes.

There is no Python reference for this parameter.

Multiple Value
Identified_Site_Identifier_Field

Dialog Reference

Select the field that uniquely identifies each identified site feature.

There is no Python reference for this parameter.

String
Identified_Site_Type_Field

Dialog Reference

Select the field that defines identified site type.

There is no Python reference for this parameter.

String
Identified_Site_Buffer_Distance_Field

Dialog Reference

Specify the desired qualifying area/building buffer selection distance value and linear units of measure. The default value is 300 feet.

There is no Python reference for this parameter.

Linear unit

Database_Date_for_Identified_Sites

(Optional)

Dialog Reference

Specify the field that records the date at which your identified site features were added to your pipeline database.

There is no Python reference for this parameter.

String

Discovery_Date_Field_for_Identified_Sites

(Optional)

Dialog Reference

Specify the field that records the ‘discovery date’ of your identified site features.

There is no Python reference for this parameter.

String
Input_Pipe_Segment_Features

Dialog Reference

Specify your input pipe segment features/records.

There is no Python reference for this parameter.

Table View
Pipe_Segment_Centerline_Identifier_Field

Dialog Reference

Specify the field that uniquely identifies the centerline segment on which the pipe segment feature/record occurs.

There is no Python reference for this parameter.

Field
Pipe_Segment_Begin_Measure_Field

Dialog Reference

Specify the field containing the begin measure value of the pipe segment feature/record on the underlying centerline feature.

There is no Python reference for this parameter.

Field
Pipe_Segment_End_Measure_Field

Dialog Reference

Specify the field containing the end measure value of the pipe segment feature/record on the underlying centerline feature.

There is no Python reference for this parameter.

Field
Pipe_Segment_Outside_Diameter_Field

Dialog Reference

Specify the field that stores the outside diameter (in inches) of the pipe segment feature/record.

There is no Python reference for this parameter.

Field
Input_MAOP_Features

Dialog Reference

Specify your input MAOP features/records.

There is no Python reference for this parameter.

Table View
MAOP_Centerline_Identifier_Field

Dialog Reference

Specify the field that uniquely identifies the centerline segment on which the MAOP feature/record occurs.

There is no Python reference for this parameter.

Field
MAOP_Begin_Measure_Field

Dialog Reference

Specify the field containing the begin measure value of the MAOP feature/record on the underlying centerline feature.

There is no Python reference for this parameter.

Field
MAOP_End_Measure_Field

Dialog Reference

Specify the field containing the end measure value of the MAOP feature/record on the underlying centerline feature.

There is no Python reference for this parameter.

Field
MAOP_Field

Dialog Reference

Specify the field that stores the MAOP value (in PSI) of the MAOP feature/record.

There is no Python reference for this parameter.

Field
PIR_Factor

Dialog Reference

Enter the PIR combustion factor for the PIR calculation. 0.69, the factor for ‘dry’ natural gas, is the default value.

There is no Python reference for this parameter.

Double

Additional_Tolerance_for_

PIR__Feet_

(Optional)

Dialog Reference

Enter an additional tolerance (in Feet) to add to the PIR, if desired. The default value is 0 feet.

There is no Python reference for this parameter.

Double
Input_External_Class_Location_Features

Dialog Reference

Specify your input external Class Location features or records.

There is no Python reference for this parameter.

Table View
External_Class_Location_Centerlin_Identifier_Field

Dialog Reference

Specify the field that uniquely identifies the centerline segment on which each Class Location feature/record occurs.

There is no Python reference for this parameter.

Field
External_Class_Location_Begin_Measure_Field

Dialog Reference

Specify the field containing the begin measure value of the Class Location feature/record on the underlying centerline feature.

There is no Python reference for this parameter.

Field
External_Class_Location_End_Measure_Field

Dialog Reference

Specify the field containing the end measure value of the Class Location feature/record on the underlying centerline feature.

There is no Python reference for this parameter.

Field

External_Class_Location_

Class_Field

Dialog Reference

Specify the field that represents the class value of the Class Location feature.

There is no Python reference for this parameter.

Field
Output_Project_Database

Dialog Reference

Specify the destination of the output project geodatabase.

There is no Python reference for this parameter.

Workspace

Code sample

The following script demonstrates how to use the HCA (Method 1 – External Class Location Data) master tool with file geodatabase data.

# Import GasHCA Library
import hcapy
# improt Gas HCA Tools
arcpy.ImportToolbox(“C:\Python27\ArcGIS10.6\Lib\site-packages\hcapy\esri\Toolboxes\GasHCA Master Tools (Desktop)
.tbx”)
Project_Name = “HCAMethod1ExternalClassLocationData”
Input_Centerline_Features = r”C:\projects\GasHCA_Enhancements\Test.gdb\StationSeries”
Centerline_Identifier_Field = “EVENTID”
Centerline_Begin_Measure_Field = “BEGIN_MEASURE”
Centerline_End_Measure_Field = “END_MEASURE”
Input_Structure_Features = r”C:\projects\GasHCA_Enhancements\Test.gdb\Structure_BIHO”
Structure_Identifier_Field = “EVENTID”
Number_of_Dwelling_Units_Field = “Num_Units”
Number_of_Stories_Field = “Num_Stories
Structure_Buffer_Distance = 660
Discovery_Date_Field_for_Structures = None
Database_Date_Field_for_Structures = None
Input_Identified_Site_Features = r”C:\projects\GasHCA_Enhancements\Test.gdb\Identified_Site”
Identified_Site_Identifier_Field = “StructorSiteID”
Identified_Site_Type_Field = “Identified_Site_Type”
Database_Date_for_Identified_Sites = None
Discovery_Date_Field_for_Identified_Sites = None
Input_Pipe_Segment_Features = r”C:\projects\GasHCA_Enhancements\Test.gdb\PipeSegment”
Pipe_Segment_Centerline_Identifier_Field = “RouteEventID”
Pipe_Segment_Begin_Measure_Field = “BEGIN_MEASURE”
Pipe_Segment_End_Measure_Field = “END_MEASURE”
Pipe_Segment_Outside_Diameter_Field = “Outsidediameter”
Input_MAOP_Features = r”C:\projects\GasHCA_Enhancements\Test.gdb\MAOP”
MAOP_Centerline_Identifier_Field = “RouteEventID”
MAOP_Begin_Measure_Field = “BEGIN_MEASURE”
MAOP_End_Measure_Field = “END_MEASURE”
MAOP_Field = “ActualPressure”
PIR_Factor = 0.69
Additional_PIR_Tolerance__Feet_ = 0
Input_External_Class_Location_Features = r”C:\temp\ExternalDOTClass”
External_Class_Location_Centerline_Identifier_Field = “ROUTEID”
External_Class_Location_Begin_Measure_Field = “BEGIN_MEASURE”
External_Class_Location_End_Measure_Field = “END_MEASURE”
External_Class_Location_Class_Field = “Class”
Output_Project_Geodatabase = r”C:\projects\GasHCA_Enhancements\A_DOTCLass_Test7.gdb”
# Execute Tool
HCAMethod1ExternalClassLocationData (Project_Name, Input_Centerline_Features, Centerline_Identifier_Field, Centerline_Begin_Measure_Field, Centerline_End_Measure_Field, Input_Structures_Features, Structure_Identifier_Field, Number_of_Dwelling_Units_Field, Number_of_Stories_Field, Structure_Buffer_Distance, Database_Date_Field_for_Structures, Discovery_Date_Field_for_Structures, Input_Identified_Site_Building_Features, Identified_Site_Building_Identifier_Field, Identified_Site_Building_Type_Field, Identified_Site_Buffer_Distance, Database_Date_for_Identified_Sites_Buildings, Discovery_Date_Field_for_Identified_Sites_Buildings, Input_PipeSegment_Features, Pipe_Segment_Centerline_Identifier_Field, PipeSegment_Begin_Measure_Field, PipeSegment_End_Measure_Field, PipeSegment_Outside_Diameter_Field, Input_MAOP_Features, MAOP_Centerline_Identifier_Field, MAOP_Begin_Measure_Field, MAOP_End_Measure_Field, MAOP_Field, PIR_Factor, Additional_PIR_Tolerance__Feet_, Input_External_Class_Location_Features, External_Class_Location_Centerline_Identifier_Field, External_Class_Location_Begin_Measure_Field, External_Class_Location_End_Measure_Field, External_Class_Location_Class_Field, Output_Project_Geodatabase)

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 Gas 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.

Related topics

Tags

Initialize Database, Pipeline, Centerline, Geodatabase, Building Intended for Human Occupancy, BIHO, Class Location, Qualifying Areas, Qualifying Buildings, Identified Site, Class Location, pipe segment, diameter, maximum allowable operating pressure, MAOP, potential impact radius, PIR, High Consequence Area, HCA.

Credits

Copyright © 2016-2020 by G2 Integrated Solutions, LLC. All Rights Reserved.

Use limitations

HCA Calculation (Method 1 – External Class Location Data) does not currently include calculation of Moderate Consequence Area (MCA) ranges. You may use the Esri Overlay Route Events tool to overlay method 1 and method 2 results, and thereby update method 1 HCA results with MCA ranges identified with the HCA Calculation (Method 2) tool.