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Fire Perimeter Functions
This module contains two convienence functions (Import and Extract) and a host of low level functions for dealing with fire perimeter data. The import function is called by the user in the configuration script and includes the input data parameters and analysis options. the extract function is called for the fire perimeter data during the more general call to Study.Extract().
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Fire perimeter shapefile import convienence function
Inputs
study the study object
inshape fire perimeter polygon shapefile
datefield name of fire date field
datetype format of date field ( YYYY | YYYYMMDD )
Options (see named option functions for specifics)
count create summary rasters (count,min,max,range)
pointinterval Compute the previous fire date for datagrid
extract Extract the case history data (rasters)
adddates add unique dates to study
exporttable export the point-event table
This function first calls preparation function to copy, standardize
and intersect overlapping fires. Then all the option functions
except for extract are called. The extract function is called after
all the data is imported and any additional sample dates are added
to the date list using option [adddates=True].
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Extract Case History Data from a Fire Perimeter Series
This Function takes an imported fire perimeter polygon history
and extracts three reserved data variable names for each point
and date combination in the study. This means there should only
be one fire history imported into a study. Previous data will be
overwritten with a second call to extract.
Input
study study object
varname name of the source variable ("FIRE")
Output: (none) Adds paths to data files to study variables list
BURN Fire occurs during [Start < FireDate <= End]
SAGE Time since fire at SDATE (0 if fire on SDATE)
EAGE Time since fire at EDATE (pre-fire tsf if BURN is 1)
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Prepare / Import the input fire perimeter history.
Inputs
Input variables defined in ImportFirePerims()
Procedure
Create data directory at StudyDir/FIRE
Copy perimeter shapefile to [datashp]
Copy and convert date field to EVTDATE
Add study area polygons at [startdate] and [enddate]
Intersect [datashp] * [pointgrid] -> [rawdatagrid]
adddates add fire occurrence dates to study dates
Outputs
datashape.shp Fire perimeter shapefile
datagrid.shp Fire occurrence point grid
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Compute rasters summarizing the period [start <= t < end]
Inputs
rawdatagrid fire point grid
cellsize output cellsize
Outputs: rasters of the same size as studyarea giving
count : count of fires
min : first fire
max : last fire
range : max - min
meanint : [(count-1) / (max-min)]
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Populate the fire points with the data about the previous fire PREVSTATE : Id number of previous fire PREVDATE : date of previous fire |
Extract fire occurrence rasters for each sample period BURN = (0|1) Fire occurs during [SDATE < t <= EDATE] |
Extract Time Since Fire for each sample period SAGE = Time Since Fire at SDATE (0 for fires on SDATE) EAGE = Time Since Fire at EDATE (Age at Burn for fires on EDATE) |
Prepare / Import the input fire perimeter history.
Inputs
Input variables defined in ImportFirePerims()
Procedure
Create data directory at StudyDir/FIRE
Copy perimeter shapefile to [datashp]
Copy and convert date field to EVTDATE
Add study area polygons at [startdate] and [enddate]
Intersect [datashp] * [pointgrid] -> [rawdatagrid]
adddates add fire occurrence dates to study dates
Outputs
datashape.shp Fire perimeter shapefile
datagrid.shp Fire occurrence point grid
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