Atlas of digital polygon fire extents for Idaho and western Montana (1889-2003)

Metadata:

Data_Quality_Information:

Attribute_Accuracy:

Attribute_Accuracy_Report:

These data were generated from a diverse collection of Forest Service and National Park Service geographic information system (GIS) coverages of unknown spatial and temporal accuracy. Human errors in mapping and digitizing fire perimeters, and/or process steps taken to create this coverage may have contributed to some inaccuracies in these data.

Quantitative_Attribute_Accuracy_Assessment:

Attribute_Accuracy_Value: atlas_source

Attribute_Accuracy_Explanation:

Considered entirely accurate.

Quantitative_Attribute_Accuracy_Assessment:

Attribute_Accuracy_Value: fire_year

Attribute_Accuracy_Explanation:

unknown

Logical_Consistency_Report:

The data we received from the management units were not entirely consistent in projection, attribution, time period reported, scale of resolution, physical location, form of GIS (e.g., shapefiles versus coverages), and completeness. We addressed these differences as described below.

Completeness_Report:

Different management units reported fire polygons over different time periods, as follows:
Bitterroot National Forest: 1889 - 2003
Boise National Forest: 2000 - 2003
Caribou-Targhee National Forest: 1988, 1994, 2000, 2002
Clearwater National Forest: 1889 - 2003
Flathead National Forest: 1984 - 2003
Frank Church Area Fire Atlas: 1889 - 2003
Glacier National Park: 1973 - 2003
Idaho Panhandle National Forest: 1889 - 1987
Kootenai National Forest: 1911 - 2003
Lolo National Forest: 1889 - 2003
Nez Perce National Forest: 1889 - 2003
Payette National Forest: 1944 - 2003
Salmon-Challis National Forest: 1889 - 2003
Sawtooth National Forest: 1953 - 2003
Yellowstone National Park: 1889 - 2003
We do not know if all fires were detected and mapped. For example, the minimum mapping unit is currently less than 20 hectares (50 acres) but likely varied through time and among management units.

Positional_Accuracy:

Horizontal_Positional_Accuracy:

Horizontal_Positional_Accuracy_Report:

Individual fires were sometimes recorded by more than one fire-management unit and sometimes had slightly different perimeters. See 'process step' for methods used to resolve conflicting data. We used visual inspection of topology and attributes, comparison to original source data, and the REGIONCLEAN command in ArcINFO to confirm the topological integrity of the final coverage.

Lineage:

Process_Step:

Process_Description:

Convert to polygon coverages:

Convert all source data not in coverage form to polygon coverage.

Process_Date: Unknown

Process_Step:

Process_Description:

Clean attribute tables:

Cleaned attribute tables to retain only fire year and management unit. Irrelevant items (columns) were deleted using the DROPITEM command.

Process_Date: Unknown

Process_Step:

Process_Description:

Create coverages for each year recorded by each management unit:

We extracted data by year from each fire history coverage to create one polygon coverage per year per management unit. For example, we created one polygon coverage for all of the fires that burned in 2000 and were mapped in the original Bitterroot National Forest fire history coverage. We utilized small, in-house AMLs customized for the particular source data (mainly dependent on whether the data was represented with ArcGIS Regions or Polygons). RESELECT being the common, lynch-pin Arc command.

Process_Date: Unknown

Process_Step:

Process_Description:

Add attributes to all attribute tables:

The following items (columns) were added to each coverage: atlas_source (character, 20, 20) and fire_year (short integer 6, 6) and populated with information received from the management units. Island polygons, i.e., small polygons within larger ones, constituted 0.8% of the total fire extent reported. We assigned them a '0' for fire_year and did not include them in our analyses of the data.

Process_Date: Unknown

Process_Step:

Process_Description:

Check for and correct errors:

We visually inspected the coverages for each year for duplicated polygons, sliver polygons (e.g., polygons of less than one acre and/or perfect geometric shapes not relatable to other attributes), or errant islands (e.g. year '0' but not completely contained within another polygon). In addition, the perimeters provided by the management units were compared to data from the Region 1 Cohesive Strategy. We also compared perimeters among adjacent National Forests that reported fires from the same area (where available) and earlier versions of their fire perimeter coverages (also where available). Very small polygons (<1 acre) with regular shapes (e.g. triangle) were deleted. Islands <1 acre were dissolved into the surrounding polygon.

For each year, we used simple overlay selection (in ArcMap) to detect duplicate polygons (in other words, two polygons with similar extent in the same place) and partially overlapping polygons. We assumed that the same area would not burn twice in the same fire season. We recognize that there may be exceptions (for example, a surface fire early in the season followed by a crown fire later in the season) but we assumed these exceptions were rare. We also assumed that each land manager had more accurate data on the extent of fires that occurred within their boundaries than any other land manager. We used these two assumptions to resolve duplicate and partially overlapping polygons as follows:

1) If duplicate polygons were wholly or partially within the boundary of one land management unit, we deleted the polygon from the other management unit.

2) If overlapping polygons did not appear to be duplicates, we used this process: UNION the two polygons, DISSOLVE the resultant polygon by year and set 'source' item to Source1/Source2 to reflect it's origins. This was common at land management boundaries associated with the Frank Church Wilderness Area fire atlas, which resulted in the selection of pre-merged polygons where atlas_source item is populated as 'ALWRI' (Aldo Leopold Wilderness Research Institute).

Rarely, we found polygons in regional coverages (i.e., Regional 1 Cohesive Strategy data) that were not reported in the Forest coverages. We investigated the possibility of a mis-attribution in the regional coverage (i.e. 'year' incorrectly labeled) by comparing the polygon to polygons of any year from the National Forest data. If a match was not found and the polygon was within one of the Forests, it was included and atlas_source was set to R1. This most commonly occurred within the Beaverhead-Deerlodge National Forest boundary, as this Forest manages lands within the study area and did not have a digital fire history.

ATLAS_SOURCE populated as "Clearwater NF" includes some fire perimeters that burned on the Nez Perce National Forest because the Clearwater National Forest fire history completely overlapped that of the Nez Perce. Similarly, Frank Church Wilderness Area Fire (ATLAS_SOURCE populated ALWRI) annual polygons include Boise National Forest fire perimeters because we were unable to work with the data provided by the Boise National Forest.

Process_Date: Unknown

Process_Step:

Process_Description:

Create annual polygon fire coverages:

Joined source annual coverages into annual regional (northern Rocky Mountain region) coverages using MAPJOIN coverage. For example, 2000 Bitterroot NF + 2000 Salmon-Challis NF + 2000 Kootenai NF + 2000 Glacier NP = 2000 fires.

Process_Date: Unknown

Process_Step:

Process_Description:

Create a single regional coverage:

Used POLYREGION and UNION to combine individual regional annual coverages into a single coverage.

Process_Date: Unknown

Process_Step:

Process_Description:

Build regional polygon fire coverages:

Used REGIONDISSOLVE command to build fire_year and atlas_source subclasses (regions).

Process_Date: Unknown

Spatial_Data_Organization_Information:

Direct_Spatial_Reference_Method: Vector

Point_and_Vector_Object_Information:

SDTS_Terms_Description:

SDTS_Point_and_Vector_Object_Type: Complete chain

Point_and_Vector_Object_Count: 27160

SDTS_Terms_Description:

SDTS_Point_and_Vector_Object_Type: Label point

Point_and_Vector_Object_Count: 13521

SDTS_Terms_Description:

SDTS_Point_and_Vector_Object_Type: GT-polygon composed of chains

Point_and_Vector_Object_Count: 13521

SDTS_Terms_Description:

SDTS_Point_and_Vector_Object_Type: Point

Point_and_Vector_Object_Count: 475

SDTS_Terms_Description:

SDTS_Point_and_Vector_Object_Type: GT-polygon composed of rings

Point_and_Vector_Object_Count: 18

SDTS_Terms_Description:

SDTS_Point_and_Vector_Object_Type: GT-polygon composed of rings

Point_and_Vector_Object_Count: 112

SDTS_Terms_Description:

SDTS_Point_and_Vector_Object_Type: GT-polygon composed of rings

Point_and_Vector_Object_Count: 6095

Spatial_Reference_Information:

Horizontal_Coordinate_System_Definition:

Planar:

Map_Projection:

Map_Projection_Name: Albers Conical Equal Area

Albers_Conical_Equal_Area:

Standard_Parallel: 46

Standard_Parallel: 48

Longitude_of_Central_Meridian: -109.5

Latitude_of_Projection_Origin: 44

False_Easting: 600000.000000

False_Northing: 0

Planar_Coordinate_Information:

Planar_Coordinate_Encoding_Method: coordinate pair

Coordinate_Representation:

Abscissa_Resolution: 0.00001

Ordinate_Resolution: 0.00001

Planar_Distance_Units: meters

Geodetic_Model:

Horizontal_Datum_Name: North American Datum of 1983

Ellipsoid_Name: Geodetic Reference System 80

Semi-major_Axis: 6378137

Denominator_of_Flattening_Ratio: 298.257222

Entity_and_Attribute_Information:

Overview_Description:

Entity_and_Attribute_Overview:

DATA FILES

The fire atlas consists of 4 files, each of which contain 6 attributes that are automatically generated by the GIS (FID, shape, area, perimeter, XXX#, and XXX-ID, where XXX is the file name) and 2 attributes that we input (atlas_source and fire_year).

1) Detailed_Description: The Northern Rocky Mountain fire atlas
Entity_Type: REGIONS polygon coverage
Entity_Type_Label: nrocky_fire.pat

2) Detailed_Description: A REGION containing only the atlas_source attribute (i.e., no fire year included), that we created so that the fire records from all years contributed by a single management unit could be easily extracted (but see note below: ATLAS_SOURCE does not always indicate the land management unit within which the fire burned).
Entity_Type:
Entity_Type_Label: nrocky_fire.patatlas_source

3) Detailed_Description: A REGION containing only the fire_year attribute (i.e., no data source information), that we created so that the fire records for a single year could be displayed or extracted easily.
Entity_Type: REGIONS polygon coverage
Entity_Type_Label: nrocky_fire.patfire_year

4) Detailed_Description: A REGION containing individual polygons for each fire with associated fire_year and atlas_source items.
Entity_Type: REGIONS polygon coverage
Entity_Type_Label: nrocky_fire.patpoly

Attributes include:

1) Attribute: Automatically generated
Attribute_Label: FID
Attribute_Definition: Internal feature number.
Attribute_Definition_Source: ESRI
Unrepresentable_Domain: Sequential unique whole numbers that are automatically generated.

2) Attribute: Automatically generated
Attribute_Label: Shape
Attribute_Definition: Feature geometry.
Attribute_Definition_Source: ESRI
Unrepresentable_Domain: Coordinates defining the features.

3) Attribute: Automatically generated
Attribute_Label: AREA
Attribute_Definition: Area of feature in internal units squared.
Attribute_Definition_Source: ESRI
Unrepresentable_Domain: Positive real numbers that are automatically generated.

4) Attribute: Automatically generated
Attribute_Label: PERIMETER
Attribute_Definition: Perimeter of feature in internal units.
Attribute_Definition_Source: ESRI
Unrepresentable_Domain: Positive real numbers that are automatically generated.

5) Attribute: Automatically generated
Attribute_Label: XXX#, where XXX is the file name
Attribute_Definition: Internal feature number.
Attribute_Definition_Source: ESRI
Unrepresentable_Domain: Sequential unique whole numbers that are automatically generated.

6) Attribute: Automatically generated
Attribute_Label: XXX-ID, where XXX is the file name
Attribute_Definition: User-defined feature number.
Attribute_Definition_Source: ESRI

7) Attribute: The management unit that provided the original fire polygon.
Attribute_Label: ATLAS_SOURCE
Attribute_Definition: See table below. Note that ATLAS_SOURCE does not always indicate the land management unit within which the fire burned. For example, the perimeters of some fires that burned on the Nez Perce National Forest have an ATLAS_SOURCE of "Caribou_Targhee NF" because the data were provided by the Caribou-Targhee National Forest.
Attribute_Definition_Source: Obtained from the management unit recording the data.

ATLAS_SOURCE = Definition
ALWRI = Aldo Leopold Wilderness Research Institute
ALWRI Salmon_Challis = Aldo Leopold Wilderness Research Institute/Salmon-Chalis National Forest
Bitterroot NF = Bitterroot National Forest
Boise NF = Boise National Forest
Caribou_Targhee NF = Caribou-Targhee National Forest
Clearwater NF = Clearwater National Forest
Flathead NF = Flathead National Forest
Glacier NP = Glacier National Park
Idaho Panhandle NF = Idaho Panhandle National Forest
Kootenai NF = Kootenai National Forest
Kootenai_NF = Kootenai National Forest
Lolo NF = Lolo National Forest
Nez Perce NF = Nez Perce National Forest
Payette NF = Payette National Forest
R1 = Region 1 Cohesive Strategy (polygon fire history coverage)
Salmon_Challis NF = Salmon-Chalis National Forest
Sawtooth NF = Sawtooth National Forest
Yellowstone NP = Yellowstone National Park

8) Attribute: The year that the fire burned.
Attribute_Label: FIRE_YEAR
Attribute_Definition: A year between 1889 and 2003. There are some 0 years (see above for explanation).
Attribute_Definition_Source: Obtained from the management unit recording the data.



SUPPLEMENTAL FILES

\Supplements\Gibson_2006_MSThesis_NorthernRockyMtn_Polygon_Fire_History.pdf: Portable Document Format file for Gibson M.S. Thesis "A northern rocky mountain polygon fire history: accuracy, limitations, strengths, applications, and recommended protocol of digital fire perimeter data."

Entity_and_Attribute_Detail_Citation:

None provided

Metadata_Reference_Information:

Metadata_Date: 20250117

Metadata_Contact:

Contact_Information:

Contact_Organization_Primary:

Contact_Organization: USDA Forest Service, Rocky Mountain Research Station

Contact_Person: Carly Gibson

Contact_Address:

Address_Type: mailing and physical

Address: 19777 Greenley Road

City: Sonora

State_or_Province: CA

Postal_Code: 95370

Country: USA

Contact_Voice_Telephone: 209-532-3671 ext 444

Contact Instructions: This contact information was current as of the original publication date. For current information see Contact Us page on: https://doi.org/10.2737/RDS.

Metadata_Standard_Name: Content Standard for National Biological Information Infrastructure Metadata

Metadata_Standard_Version: FGDC-STD-001.1-1999