Prepare Centerline Buffers

The Prepare Centerline Buffers tool creates centerline buffer layers for use in subsequent selection of Buildings Intended for Human Occupancy (BIHOs) and Qualifying Areas/Buildings for Class Location analysis per the requirements of 49 CFR §192.5 Class Locations. Prepare Centerline Buffers produces four output feature classes in the Gas HCA Tool project geodatabase:

  • DC_CENTERLINE_STRUCTURE_BUFFER – This output feature class is based on the Class Location 660-foot (200-meter) buffer radius that defines the width of Class Location units. Separate buffer features are generated for each input CENTERLINE feature; these buffers are used to associate BIHOs with CENTERLINE features in subsequent Class Location analysis workflow steps.
  • DC_CENTERLINE_STRUCTURE_BUFFER_DISSOLVED – This output feature class is derived by spatially “dissolving” the individual buffer features of the DC_CENTERLINE_STRUCTURE_BUFFER feature class; overlapping features are merged (dissolved) into single features. DC_CENTERLINE_STRUCTURE_BUFFER_DISSOLVED features are used in display to visualize the width of the Class Location units; they are also used to spatially select those BIHOs that must be included in the Class Location analysis (per 49 CFR §192.5(a)(1)). (Note that each separate dwelling unit in a multiple dwelling unit building is counted as a separate BIHO unit for the purposes of Class Location determination, per 49 CFR §192.5(a)(2).)
  • DC_CENTERLINE_QUALIFIED_AREA_BUFFER – This output feature class is based on the Class Location 300-foot (91-meter) buffer radius that defines the selection distance for Qualifying Areas and Buildings (i.e., per 49 CFR §192.5(b)(3)(ii)), buildings or a small, well-defined outside areas (such as a playgrounds, recreation areas, outdoor theaters, or other places of public assembly) that are occupied by 20 or more persons on at least 5 days a week for 10 weeks in any 12-month period. (The days and weeks need not be consecutive.) Separate buffer features are generated for each input CENTERLINE feature; these buffers are used to associate Qualifying Areas/Buildings with CENTERLINE features in subsequent Class Location analysis workflow steps.
  • DC_CENTERLINE_QUALIFIED_AREA_BUFFER_DISSOLVED – This output feature class is derived by spatially ”dissolving” the individual buffer features of the DC_CENTERLINE_QUALIFIED_AREA_BUFFER feature class; overlapping features are merged (dissolved) into single features. DC_CENTERLINE_QUALIFIED_AREA_BUFFER_DISSOLVED features are used in display to visualize the width of the 300-foot buffer for selection of Qualifying Areas/Buildings; they are also used to spatially select those Qualifying Areas and Buildings that must be included in the Class Location analysis to help determine Class 3 locations (per 49 CFR §192.5(b)(3)(ii)).

In the Class Location analysis workflow, Prepare Centerline Buffers is typically run immediately after the Copy Centerline tool. In a typical Class Location analysis workflow, Prepare Structures and Prepare Qualifying Areas are run after Prepare Centerline Buffers.

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

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

Usage

  • 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 may increase the value, if desired, to account for uncertainty in the location of your pipeline centerline, or your structure 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, per 49 CFR §192.5(b)(3)(ii). You may increase the value, if desired, to account for uncertainty in the location of your pipeline centerline, or your Qualifying Area and Building features.
  • Input Centerline Features, Output Centerline Structure Buffer Features, Output Centerline Structure Buffer Dissolved Features, Output Centerline Qualifying Area Buffer Features, and Output Centerline Qualifying Area Buffer Dissolved Features – These parameters are all optional, and default to standard Gas HCA Tool features classes in your specified project geodatabase. You may, if desired, specify different values for these parameters, but bear in mind that the Gas HCA Tool tools look for the standard Gas HCA Tool project geodatabase schema objects automatically. Should you choose to override the default values, you will have to manage input and output data parameters in subsequent analysis steps.

Syntax

PrepareCenterlineBufferTool_hcapy (project_database, {centerline_layer}, struct_buffer_distance_value, qa_buffer_distance_value, {output_centerline_structure_buffer}, {output_centerline_structure_buffer_dis}, {output_centerline_qualified_area_buffer}, {output_centerline_qualified_area_buffer_dis})

Parameter Explanation Data Type
project_database Dialog Reference

Select a Gas HCA Tool project geodatabase created using the Initialize Database tool. By default, the output from this tool is stored in this workspace.

There is no python reference for this parameter.

Workspace
centerline_layer (Optional) Dialog Reference

 

Select your input centerline features. The tool defaults to the CENTERLINE feature class in your specified Gas HCA Tool project geodatabase.

There is no python reference for this parameter.

Feature Layer
struct_buffer_distance_value Dialog Reference

 

Specify a buffer distance value defining the width of the Class Location unit corridor. The default value is 660 feet, as specified 49 CFR §192.5(a)(1). You may increase this distance to account for uncertainty in the location of your centerline or structure features.

There is no python reference for this parameter.

Linear unit
qa_buffer_distance_value Dialog Reference

 

Specify a value defining the width of the feature selection buffer for Qualifying Areas/Buildings. The default value is 300 feet, as specified 49 CFR §192.5(b)(3)(ii). You may increase this distance to account for uncertainty in the location of your centerline or Qualifying Areas/Buildings.

 

There is no python reference for this parameter.

Linear unit
output_centerline_structure_buffer (Optional) Dialog Reference

Specify the destination of your output Class Location unit corridor polygon features. The tool defaults to the DC_CENTERLINE_STRUCTURE_BUFFER feature class in your specified Gas HCA Tool project geodatabase.

There is no python reference for this parameter.

Feature Layer
output_centerline_structure_buffer_dis (Optional) Dialog Reference

Specify the destination of your output dissolved Class Location unit corridor polygon features. The tool defaults to the DC_CENTERLINE_STRUCTURE_BUFFER_DISSOLVED feature class in your specified Gas HCA Tool project geodatabase.

There is no python reference for this parameter.

Feature Layer
output_centerline_qualified_area_buffer (Optional) Dialog Reference

Specify the destination of your output selection distance buffer polygons for Qualifying Areas/Buildings. The tool defaults to the DC_CENTERLINE_QUALIFIED_AREA_BUFFER feature class in your specified Gas HCA Tool project geodatabase.

There is no python reference for this parameter.

Feature Layer
output_centerline_qualified_area_buffer_dis (Optional) Dialog Reference

Specify the destination of your output dissolved selection distance buffer polygons for Qualifying Areas/Buildings. The tool defaults to the DC_CENTERLINE_QUALIFIED_AREA_BUFFER_DISSOLVED feature class in your specified Gas HCA Tool project geodatabase.

There is no python reference for this parameter.

Feature Layer

Code Samples

Initialize Database
import hcapy
arcpy.ImportToolbox(“C:/Workspace/hcapy/src/hcapy/esri/Toolboxes/Gas HCA Tools.pyt”)
project_name= “HCARun”
out_project_database = r”C:TempHCA.gdb”
arcpy.PrepareCenterlineBuffer_hcapy (project_name, project_database = out_project_database)

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

Gas HCA, Qualifying Area, Qualifying Building, BIHO, Class Location, location unit

Credits

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

Use limitations

There are no access and use limitations for this item.