HCA CALCULATION (METHOD 1)

Summary

HCA Calculation (Method 1) determines High Consequence Area (HCA) ranges by method 1 (per 49 CFR §192.903(1)) using Class Location units generated by the Class Location Calculation tool. The tool designates as an HCA all centerline ranges meeting any of the following criteria:

(i) A Class 3 location under §192.5; or

(ii) A Class 4 location under §192.5; or

(iii) Any area in a Class 1 or Class 2 location where the potential impact radius is greater than 660 feet (200 meters), and the area within a potential impact circle contains 20 or more buildings intended for human occupancy; or

(iv) Any area in a Class 1 or Class 2 location where the potential impact circle contains an identified site.

Usage

Input Structure and Site Segment Features – This tool uses as input the Building Intended for Human Occupancy (BIHO) and identified site segments created by the Create Structure and Site PIR Buffers tool. Unless otherwise specified, the tool defaults this parameter to the HCA_STRUCTURESEGMENT feature class in your selected Gas HCA Tool project geodatabase.
Class Type – When set to ‘Class Clustered,’ the tool uses ‘clustered’ Class Location features in the calculation. When set to ‘Class Unclustered,’ the tool uses unclustered Class Location features in the calculation.
Input Class Location Features – This tool uses as input the Class Location unit range features created by the Class Location Calculation tool. Unless otherwise specified, the tool defaults this parameter to the DOT_CLASS_RANGE_CLUSTERED feature class in your selected Gas HCA Tool project geodatabase when Class Type is set to ‘Class Clustered.’ If Class Type is set to ‘Class Unclustered,’ this parameter defaults to the DOT_CLASS_RANGE_UNCLUSTERED feature class in your selected Gas HCA Tool project geodatabase.
Output HCA Range Features – This parameter defines the destination of the output HCA range features. Unless otherwise specified, the default destination for the output HCA range features is the HCA_RANGE_M1 feature class in your selected Gas HCA Tool project geodatabase.
Output HCA Segment Features – This parameter defines the destination of the output dynamically segmented HCA range features, which contain useful information, such as BIHO and identified site counts, and the provenance of the segment. Unless otherwise specified, the default destination for the output HCA segment features is the HCA_SEGMENT_COUNT_M1 feature class in your selected Gas HCA Tool project geodatabase.

In a typical method 1 HCA workflow, HCA Calculation (Method 1) follows Create Structure and Site PIR Buffers and is the final process step in the workflow.

Syntax

HCAMethod1ATool_hcapy (project_database, class_type, {hca_range}, {hca_segment_count_out})

Parameter	Explanation	Data Type
project_database	Dialog Reference Select a Gas HCA Tool project geodatabase created using the Initialize Database tool. The output from this tool is stored in this workspace by default. There is no Python reference for this parameter.	Workspace
input_hca_structure_segments (Optional)	Dialog Reference Specify your input road BIHO and identified site PIR segment features. There is no Python reference for this parameter.	Feature Layer
class_type	Dialog Reference Specify the desired class output calculation. The available options are ‘Clustered’ and ‘Unclustered.’ There is no Python reference for this parameter.	String
input_dot_class (Optional)	Dialog Reference Specify your input (clustered or unclustered) Class Location features. There is no Python reference for this parameter.	Feature Layer
hca_range (Optional)	Dialog Reference Specify the destination of the output HCA range features. There is no Python reference for this parameter.	Feature Layer
hca_segment_count_out (Optional)	Dialog Reference Specify the destination of the output HCA segment features. There is no Python reference for this parameter.	Feature Layer

Code sample

HCA Calculation (Method 1)

# Import GasHCA Library

import hcapy

# improt Gas HCA Tools

arcpy.ImportToolbox(“C:\Python27\ArcGIS10.6\Lib\site-packages\hcapy\esri\Toolboxes\Gas HCA Tools.pyt”)

project_database = r”C:\projects\GasHCA_Enhancements\A_DOTCLass_Test5.gdb”

class_type = “Clustered”

# Execute tool

arcpy.HCAMethod1A_hcapy(project_database, class_type = class_type)

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.

Credits

Use limitations

HCA Calculation (Method 1) 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.