National Wildfire Coordinating Group

Run Analysis & Update Metadata

Run Analysis

Several geographic calculations and analyses are commonly used to answer questions posed during a wildfire incident.

Calculations should only be run on an Offline Copy. Never run any processes or tools on the entire National Incident Feature Service.

Required Geometry calculations:

  • For new or updated Event Polygons, calculate Acres using the Calculate Geometry tool or Python.
  • For new or updated Event Lines and Perimeter Lines, calculate Length in Feet using the Calculate Geometry tool or Python.
  • For new or updated Event Points and Accountable Property, calculate Latitude and Longitude using Python and .cal files in the \tools folder to ensure coordinates are rounded to 3 decimal places.

Note: Always perform geometry calculations on a selection of data, never on the entire dataset.

Other common analyses include:

  • Calculating area by ownership
  • Calculating line length(s) by feature category
  • Calculating percent containment

Instructions are included for calculating geometry, calculating area by ownership, calculating line length(s) by feature category, and calculating percent containment.

Note: The US Survey Foot has been deprecated as of January 1, 2023. Use ‘International Foot’ and ‘International Acres’ for calculations.

Calculate Geometry 

As of Pro 2.9, the Calculate Geometry tool provides both Geodesic and Planar options. Geodesic calculations may differ slightly from planar calculations for very large fires. Discuss with the incident SITL if there is any doubt in which to use, consistency is key when reporting.

Acres

  1. From the attribute table, select the features to update geometry and right-click the Acres column header and select Calculate Geometry.
    Event Polygon table with Acres selected and Calculate Geometry highlighted.
  2. The Calculate Geometry window will open.
    Select Acres as the Field and International Acres as the Area Unit.
    Select Area for a planar calculation or Area (geodesic) for a geodesic calculation.
    Populate the Coordinate System to the local Projected Coordinate System.
    Calculate Geometry Window with box around Area (geodesic) selection.

Length

  1. From the attribute table, select the features to update geometry and right-click the Acres column header and select Calculate Geometry.
    Event Line table with LengthFeet selected and Calculate Geometry highlighted.
  2. The Calculate Geometry window will open.
    Select LengthFeet as the Field and Feet as the Area Unit.
    Select Area for a planar calculation or Area (geodesic) for a geodesic calculation.
    Populate the Coordinate System to the local Projected Coordinate System.
    Calculate Geometry window with International Feet selected as the length unit.

 

Calculate Geometry with Python

In earlier version of Pro, it was sometimes necessary to use a Python expression to calculate feature geometry. Geodesic calculations may differ slightly from planar calculations for very large fires. Discuss with the incident SITL if there is any doubt in which to use, consistency is key when reporting.

Calculate Area and Length with Python

These calculations will use the spatial reference of the feature class, not the map frame.

  1. Open the layer attribute table, select the features to update geometry, right-click the Acres or LengthFeet field, and select Calculate Field. Alternatively, click Calculate, and select Acres as the field name in the Geoprocessing pane.

    Event Polygon attribute table with one row selected.  Acres and Calculate Field highlighted.
  2. Enter !shape.geodesicArea​@acres! into the expression field and click Run to calculate the geodesic are of the feature(s) in acres.
    Enter !shape.geodesicLength​@FeetInt!  into the expression field and click Run to calculate the geodesic length of the feature(s) in feet.

Geoprocessing pane with GISAcres = !shape.geodesicArea​@acres! entry highlighted.
Geoprocessing pane with LenthFeet = !shape.geodesicLength​@feetint! entry highlighted.

Calculate Latitude and Longitude in WGS84DDM with Python

These calculations are independent of the spatial reference of the feature class and the map frame. The resulting coordinates will be WGS84 Degrees Decimal Minutes rounded to 3 places.

  1. Open the layer attribute table, select the features to update geometry, right-click the Acres or LengthFeet field, and select Calculate Field. Alternatively, click Calculate, and select Acres as the field name in the Geoprocessing pane.

    Event Point attribute table with Lattitude and Calculate Field highlighted.
  2. In the Calculate Field pane, click the Import button below the Code Block box.
    Calculate Field Pane with Import button highlighted.
  3. Navigate to and select the calculate_Lat.cal expression file (located in the tools folder).
    Import window open with Project, Folders and WGS84_Lat.cal and OK selected.
  4. This will populate the expression and code block with the necessary script to calculate Latitude in WGS84 DDM. Click Run. If the error “Parameter is missing or invalid” is returned, click within the Code Block window and try again.

    Geoprocessing pane showing imported Code in Code Block.  Run button is highlighted.
    Calculate field window with the Code Block section highlight with the text "Click Here"
  5. Repeat the same steps for the Longitude field but select the calculate_Long.cal expression file instead.
  6. The Latitude and Longitude fields will now be populated.
    Attribute table showing calculated Latitude and Longitude coordinates.

 

Acreage Burned by Ownership

Prior to calculating the acreage by ownership, a polygon dataset of land ownership will need to be acquired. County level parcel data is often the most accurate; however, national datasets can be used as well. Most common is the “Surface Management Agency” data from the Bureau of Land Management (BLM) (https://gbp-blm-egis.hub.arcgis.com).


 [KG1]Updated link

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  1. With the ownership data added to the map, open the Geoprocessing pane, search for, and open the Clip tool.
    Map with ownership data.  Geoprocessing pane open with Clip tool highlighted.
  2. Enter the Ownership data as the Input Features, Event Polygon as the Clip Features, and save it to an appropriate location following GeoOps naming.
    Geoprocessing window with input as ownership, clip features and event polygon and output feature class populated.
  3. Open the resulting feature class’ attribute table and add a field.
    Ownership Clip attribute table with Add Field button highlighted.
  4. Name the field Acres and set the Data Type to Double. Click Save on the Ribbon.
    Fields view with Acres and Double highlighted.
  5. Calculate the Acres field.
    Attribute table with populated Acres column highlighted.

Note: If the ownership data has multiple polygons for the same owner, Summary Statistics or Dissolve can be used to combine them.

Line Distance by Feature Category

Calculate the amount of line in the field by type.

  1. After calculating the LengthFeet field, right-click Feature Category, and select Summarize.
    Event Line attribute table with Feature Category selected and Summarize highlighted.
  2. The Summary Statistics window will open.
    Enter LengthFeet and Sum as the Field and Statistic Type. Set the output to the Other Incident Data gdb or an appropriate folder and name following GeoOps standards. Click OK.
    Summary Statistics window with Statistics Field, Statistics Type and Case field populated.
  3. The resulting table will return the total length in feet for each feature category present.
    Line Summary table by FC Line Type, Frequency and sum of length in feet.

Percent Containment

The percent containment of a fire is generally the percentage of fire edge that Ops has designated as Contained. Always check with the SITL before publishing or printing anything that displays percent containment.

There are many methods and custom tools to calculate containment. The simplest way is to open the Chart provided with the Perimeter Line after calculating the LengthFeet field and syncing the Offline Copy.

Edit Map table of contents with the Perimeter Line layer expanded and highlighted.

The Perimeter Line Containment chart showing the percent containment automatically calculated.

  1. To calculate from the polygon, on the Map tab of the ribbon, in the Inquiry section, select Measure Features from the Measure dropdown.
    Map ribbon.  Measure selected and Measure Features highlighted.
  2. Set the Distance Units to Feet under the Options and click on the current Wildfire Daily Perimeter.
    Measure Features window showing Area and Perimeter.
  3. If there are multiple polygons, click each, and the Sum portion will add them together.
  4. Take the total length of Contained features from performing a Line Distance Summary operation described above on the Perimeter Line feature class and divide that by the total Perimeter from the measure tool. E.g. 7753 / 71,798 = .1079 or 10.8%.

Update Metadata

After each round of edits is complete, best practice is to update the DynamicTextUpdate table in the other_incident_data.gdb with the following information:

  • Source Statement, Acres, and Acres Effective Date of the Wildfire Daily Fire Perimeter
  • Date and Operational Period for maps that will be created or updated 

screen shot of DynamicTextUpdate spreadsheet columns.

Editing the DynamicTextUpdate table should be done from the Edit Project only while all other projects are closed. Values in the DynamicTextUpdate table will be used to update multiple map elements dynamically on all map layouts. Save edits after updating the attributes of the DynamicTextUpdate table. Round Acres to the nearest whole number. Use military time for the Acres Effective Date field.

 

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Page Last Modified / Reviewed: 
2024-01-24