Table 1 Workflow for Filtering and Processing GIS Firelines and Perimeters.

1

NIFC Operations: Line

Data Acquisition

Download firelines from NIFC Operational Data archives 2017–2024 as polyline features.

2

NIFC Operations: Line

Filter

Attribute query on “FeatureCat” field for: Completed Burnout, Completed Dozer Line, Completed Fuel Break, Completed Hand Line, Completed Mixed Construction Line, Completed Plow Line, Completed Road as line.

3

NIFC Operations: Line

Filter

Attribute query on “DeleteThis” field for features labeled “Yes”.

4

NIFC WFIGS and WFM RD&A Perimeters

Data Acquisition

Download wildfire perimeters from NIFS, using the WFM RD&A perimeter dataset for incidents from 2017–2019 and WFIGS perimeters from 2020–2024.

5

NIFC Perimeters

Removing Duplicates

Conducted attribution analysis to compare perimeters with identical geometry using “Find Identical” tool in ArcGIS Pro. Attribution for duplicate perimeters selected by comparing with overlayed operations data.

6

NIFC Operations: Line

Data Cleaning

Removed leading and trailing blank spaces in IRWIN ID and Incident Name fields and added missing “{}” brackets to IRWIN ID field.

7

NIFC Perimeters and Line Operations Data

Attributing Firelines to Wildfire Perimeters

Using the IRWIN ID and Incident Name fields from perimeters, lines were attributed to specific incidents. For lines missing attribution, lines were assigned to wildfires within 5 km of perimeter. If other fires were present, analysts relied on other attribution such as upload date and geometry to manually attribute line to perimeter.

8

NIFC Perimeters

Handling Complexes and Neighboring Incidents

Dissolved perimeters of complexes into one perimeter, using incident management reports to confirm overlapping burn dates using Fire Discovery and Fire Containment fields. A new field was generated to identify dissolved perimeters.

9

NIFC Operations: Line

Visual Inspection

Manually removed erroneous lines (e.g., straight lines spanning long distances over varying topography), splitting lines at last vertex before suspect geometry to retain implemented portions of line.

10

NIFC Operations: Line

Removal Of Duplicates

Used “Delete Identical” tool to remove duplicate features based on geometry and attribution, acknowledging remaining duplicates are due to slight difference in vertices or human error.

11

NIFC Perimeters and Line Operations Data

Fireline Engagement Outcome

Buffered fire perimeters by 50 meters (50 meters within and outside of perimeter). Conducted overlay analysis to classify line status (held, burned over, and not engaged).