CCWFGM_FWI Class Reference

CFFDRS FWI Implementation. More...

#include <CWFGM_FWI.h>

Collaboration diagram for CCWFGM_FWI:

Public Member Functions
	CCWFGM_FWI ()
STDMETHOD()	HourlyFFMC_VanWagner (double in_ffmc, double rain, double temperature, double rh, double ws, ULONG seconds_since_ffmc, double *ffmc)
STDMETHOD()	HourlyFFMC_Equilibrium (double in_ffmc, double rain, double temperature, double rh, double ws, ULONG seconds_since_ffmc, double *ffmc)
STDMETHOD()	HourlyFFMC_Lawson (double in_ffmc_prevday, double in_ffmc_currday, double rain, double temperature, double rh, double ws, unsigned long seconds_into_day, double *ffmc)
STDMETHOD()	HourlyFFMC_VanWagner_Previous (double current_ffmc, double rain, double temperature, double rh, double ws, double *prev_ffmc)
STDMETHOD()	HourlyFFMC_Equilibrium_Previous (double current_ffmc, double rain, double temperature, double rh, double ws, double *prev_ffmc)
STDMETHOD()	HourlyFFMC_Lawson_Contiguous (double in_ffmc_prevday, double in_ffmc_currday, double rain, double temperature, double rh_0, double rh, double rh_1, double ws, unsigned long seconds_into_day, double *ffmc)
STDMETHOD()	HourlyFFMC_Hybrid (double in_prev_std_ffmc, double in_curr_std_ffmc, double in_ffmc, SAFEARRAY *rain48, double temperature, double rh, double ws, unsigned long seconds_into_day, double *ffmc)
STDMETHOD()	DailyFFMC_VanWagner (double in_ffmc, double rain, double temperature, double rh, double ws, double *ffmc)
STDMETHOD()	DMC (double in_dmc, double rain, double temperature, double latitude, double longitude, unsigned short month, double rh, double *dmc)
STDMETHOD()	DC (double in_dc, double rain, double temperature, double latitude, double longitude, unsigned short month, double *dc)
STDMETHOD()	FF (double ffmc, ULONG seconds_since_ffmc, double *ff)
STDMETHOD()	ISI_FWI (double ffmc, double ws, ULONG seconds_since_ffmc, double *isi)
STDMETHOD()	ISI_FBP (double ffmc, double ws, ULONG seconds_since_ffmc, double *isi)
STDMETHOD()	BUI (double dc, double dmc, double *bui)
STDMETHOD()	FWI (double isi, double bui, double *fwi)
STDMETHOD()	DSR (double fwi, double *dsr)
Public Member Functions inherited from ICWFGM_FWI
HRESULT	HourlyFFMC_VanWagner ([in]double in_ffmc, [in]double rain, [in]double temperature, [in]double rh, [in]double ws, [in]unsigned long seconds_since_ffmc, [out, retval]double *ffmc)
HRESULT	HourlyFFMC_Equilibrium ([in]double in_ffmc, [in]double rain, [in]double temperature, [in]double rh, [in]double ws, [in]unsigned long seconds_since_ffmc, [out, retval]double *ffmc)
HRESULT	HourlyFFMC_Lawson ([in]double prev_std_ffmc, [in]double curr_std_ffmc, [in]double rain, [in]double temperature, [in]double rh, [in]double ws, [in]unsigned long seconds_into_day, [out, retval]double *ffmc)
HRESULT	HourlyFFMC_VanWagner_Previous ([in]double current_ffmc, [in]double rain, [in]double temperature, [in]double rh, [in]double ws, [out, retval]double *prev_ffmc)
HRESULT	HourlyFFMC_Equilibrium_Previous ([in]double current_ffmc, [in]double rain, [in]double temperature, [in]double rh, [in]double ws, [out, retval]double *prev_ffmc)
HRESULT	HourlyFFMC_Lawson_Contiguous ([in]double in_prev_std_ffmc, [in]double in_curr_std_ffmc, [in]double rain, [in]double temperature, [in]double rh_0, [in]double rh_t, [in]double rh_1, [in]double ws, [in]unsigned long seconds_into_day, [out, retval]double *ffmc)
HRESULT	HourlyFFMC_Hybrid ([in]double in_prev_std_ffmc, [in]double in_curr_std_ffmc, [in]double in_ffmc, [in]SAFEARRAY(double) rain48, [in]double temperature, [in]double rh, [in]double ws, [in]unsigned long seconds_into_day, [out, retval]double *ffmc)
HRESULT	DailyFFMC_VanWagner ([in]double in_ffmc, [in]double rain, [in]double temperature, [in]double rh, [in]double ws, [out, retval]double *ffmc)
HRESULT	DMC ([in]double in_dmc, [in]double rain, [in]double temperature, [in]double latitude, [in]double longitude, [in]unsigned short month, [in]double rh, [out, retval]double *dmc)
HRESULT	DC ([in]double in_dc, [in]double rain, [in]double temperature, [in]double latitude, [in]double longitude, [in]unsigned short month, [out, retval]double *dc)
HRESULT	FF ([in]double ffmc, [in]unsigned long seconds_since_ffmc, [out, retval]double *ff)
HRESULT	ISI_FWI ([in]double ffmc, [in]double ws, [in]unsigned long seconds_since_ffmc, [out, retval]double *isi)
HRESULT	ISI_FBP ([in]double ffmc, [in]double ws, [in]unsigned long seconds_since_ffmc, [out, retval]double *isi)
HRESULT	BUI ([in]double dc, [in]double dmc, [out, retval]double *bui)
HRESULT	FWI ([in]double isi, [in]double bui, [out, retval]double *fwi)
HRESULT	DSR ([in]double fwi, [out, retval]double *dsr)

Detailed Description

CFFDRS FWI Implementation.

The FWI standard is the first major subsystem of the CFFDRS to be completed. It provides relative measures of fuel moisture and fire behavior potential. It is encapsulated in its own COM object. A COM interface was chosen over a regular DLL interface only so that applications programmed in other languages could use this functionality. This object does not support the standard COM IPersistStream, IPersistStreamInit, and IPersistStorage interfaces, since this object does not maintain any state information, it is only a collection of methods.

Constructor & Destructor Documentation

CCWFGM_FWI::CCWFGM_FWI ( )

inline

Default Constructor

See Also

CCWFGM_FWI::CCWFGM_FWI

Member Function Documentation

CCWFGM_FWI::BUI	(	double	dc,
		double	dmc,
		double *	bui
	)

Calculate BUI (buildup index) from DC, DMC. BUI provides a numerical, relative indication of the amount of fuel available for combustion.

Parameters

dc	DC value
dmc	DMC value
bui	Calculated BUI value

See Also

ICWFGM_FWI::BUI

Return values

E_POINTER	The BUI address provided is invalid
S_OK	Successful
E_INVALIDARG	Failure during calculation

CCWFGM_FWI::DailyFFMC_VanWagner	(	double	in_ffmc,
		double	rain,
		double	temperature,
		double	rh,
		double	ws,
		double *	ffmc
	)

Calculates daily FFMC (fine fuel moisture code), based on the previous day's FFMC and provided conditions. FFMC is a numerical rating of the moisture content of litter and other cured fine fuels.

Parameters

in_ffmc	The previous day's Van Wagner FFMC value
rain	Precipitation in the prior 24 hours (noon to noon, LST), mm
temperature	Noon (LST) temperature, Celsius
rh	Relative humidity expressed as a fraction ([0..1])
ws	Wind speed (kph) at noon LST
ffmc	Calculated FFMC value

See Also

ICWFGM_FWI::DailyFFMC_VanWagner

Return values

E_POINTER	The FFMC address provided is invalid
S_OK	Successful
E_INVALIDARG	Failure during calculation

CCWFGM_FWI::DC	(	double	in_dc,
		double	rain,
		double	temperature,
		double	latitude,
		double	longitude,
		unsigned short	month,
		double *	dc
	)

Calculates DC (drought code) given the previous day's DC and provided conditions. DC provides a numerical rating of the average moisture content of the deep (10-24 cm), compact organic layers.

Parameters

in_dc	The previous day's DC value
rain	Precipitation in the prior 24 hours (noon to noon, LST), mm
temperature	Noon (LST) temperature, Celsius
latitude	Radians, used to determine the appropriate table as defined in "Latitude Considerations in Adapting the Canadian Forest Fire Weather Index System To Other Countries", M.E. Alexander, in prep as Index X in Weather Guide for the Canadian Forest Fire Danger Rating System by B.D. Lawson, O.B. Armitage.
longitude	Radians, reserved for future use, currently unused (may be if/as/when more regional constants are defined)
month	Origin 0 (January = 0, December = 11)
dc	Calculated DC value

See Also

ICWFGM_FWI::DC

Return values

E_POINTER	The DC address provided is invalid
S_OK	Successful
E_INVALIDARG	Failure during calculation or month is greater than 11, assuming January is 0.

CCWFGM_FWI::DMC	(	double	in_dmc,
		double	rain,
		double	temperature,
		double	latitude,
		double	longitude,
		unsigned short	month,
		double	rh,
		double *	dmc
	)

Calculates daily DMC (duff moisture code) given the previous day's DMC and provided conditions. DMC provides a numerical rating of the average moisture content of the loosely compact organic layers of a moderate depth (5-10cm).

Parameters

in_dmc	The previous day's DMC value
rain	Precipitation in the prior 24 hours (noon to noon, LST), mm
temperature	Noon (LST) temperature, Celsius
latitude	Radians, used to determine the appropriate table as defined in "Latitude Considerations in Adapting the Canadian Forest Fire Weather Index System To Other Countries", M.E. Alexander, in prep as Index X in Weather Guide for the Canadian Forest Fire Danger Rating System by B.D. Lawson, O.B. Armitage.
longitude	Radians, reserved for future use, currently unused (may be if/as/when more regional constants are defined)
month	Origin 0 (January = 0, December = 11)
rh	Relative humidity expressed as a fraction ([0..1]) at noon LST
dmc	Calculated DMC value

See Also

ICWFGM_FWI::DMC

Return values

E_POINTER	The DMC address provided is invalid
S_OK	Successful
E_INVALIDARG	Failure during calculation or month is greater than 11, assuming January is 0.

CCWFGM_FWI::DSR	(	double	fwi,
		double *	dsr
	)

Calculates DSR from FWI.

Parameters

fwi	FWI value
dsr	Calculated DSR value

See Also

ICWFGM_FWI::DSR

Return values

E_POINTER	The DSR address provided is invalid
S_OK	Successful
E_INVALIDARG	Failure during calculation

CCWFGM_FWI::FF	(	double	ffmc,
		ULONG	seconds_since_ffmc,
		double *	ff
	)

Calculates f(F), which is used to calculate ISI from FFMC.

Parameters

ffmc	FFMC value
seconds_since_ffmc	Seconds since observed ffmc
ff	Calculated f(F) value

See Also

ICWFGM_FWI::FF

Return values

E_POINTER	The FF address provided is invalid
S_OK	Successful
E_INVALIDARG	Failure during calculation

CCWFGM_FWI::FWI	(	double	isi,
		double	bui,
		double *	fwi
	)

Calculates FWI (fire weather index) from ISI and BUI. FWI provides a numerical, relative rating of fire intensity.

Parameters

isi	ISI value
bui	BUI value
fwi	Calculated FWI value

See Also

ICWFGM_FWI::FWI

Return values

E_POINTER	The FWI address provided is invalid
S_OK	Successful
E_INVALIDARG	Failure during calculation

CCWFGM_FWI::HourlyFFMC_Equilibrium	(	double	in_ffmc,
		double	rain,
		double	temperature,
		double	rh,
		double	ws,
		ULONG	seconds_since_ffmc,
		double *	ffmc
	)

Calculates hourly FFMC (fine fuel moisture code), using the experimental Equilibrium mathematical model developed by K. Anderson, based on the previous hour's FFMC and provided conditions. FFMC is a numerical rating of the moisture content of litter and other cured fine fuels.

Parameters

in_ffmc	The previous time's Van Wagner FFMC value
rain	Precipitation in the prior hour, mm
temperature	Celsius
rh	Relative humidity expressed as a fraction ([0..1])
ws	Wind speed (kph)
seconds_since_ffmc	Seconds since observed FFMC
ffmc	Calculated FFMC value

See Also

ICWFGM_FWI::HourlyFFMC_Equilibrium

Return values

E_POINTER	The FFMC address provided is invalid
S_OK	Successful
E_INVALIDARG	Failure during calculation, or the parameter seconds_since_ffmc is greater than 7200 seconds

CCWFGM_FWI::HourlyFFMC_Equilibrium_Previous	(	double	in_ffmc,
		double	rain,
		double	temperature,
		double	rh,
		double	ws,
		double *	ffmc
	)

Calculates the previous hourly FFMC (fine fuel moisture code), using equilibrium mathematical model, based on the current hour's FFMC and previous hour's provided conditions. FFMC is a numerical rating of the moisture content of litter and other cured fine fuels.

Parameters

in_ffmc	The previous time's equilibrium FFMC value
rain	Precipitation in the prior hour, mm
temperature	Celsius
rh	Relative humidity expressed as a fraction ([0..1])
ws	Wind speed (kph)
ffmc	Calculated FFMC value

See Also

ICWFGM_FWI::HourlyFFMC_Equilibrium_Previous

Return values

E_POINTER	The FFMC address provided is invalid
S_OK	Successful
E_INVALIDARG	Failure during calculation.

CCWFGM_FWI::HourlyFFMC_Hybrid	(	double	in_prev_std_ffmc,
		double	in_curr_std_ffmc,
		double	in_ffmc,
		SAFEARRAY *	rain48,
		double	temperature,
		double	rh,
		double	ws,
		unsigned long	seconds_into_day,
		double *	ffmc
	)

The Van Wagner calculation provides low variability in hourly FFMC values per day but considers rainfall. The Lawson approach to FFMC values provide more variability to FFMC values through the day, but do not consider rainfall. This experimental approach returns FFMC values from one technique or another based on reported rainfall amounts over the prior 48 hours. Contact Brad Armitage for algorithmic details and summaries of results of this approach. This implementation is experimental and should be used with caution.

Parameters

in_prev_std_ffmc	The previous day's standard daily Van Wagner FFMC value
in_curr_std_ffmc	The current day's standard daily Van Wagner FFMC value
in_ffmc	The previous time's Van Wagner FFMC value
rain48	Precipitation, mm in the past 48 hours
temperature	Celsius
rh	Relative humidity expressed as a fraction ([0..1])
ws	Wind speed (kph)
seconds_into_day	Local standard time
ffmc	Calculated FFMC value

See Also

ICWFGM_FWI::HourlyFFMC_Hybrid

Return values

E_POINTER	The FFMC address provided is invalid
S_OK	Successful
E_INVALIDARG	Failure during calculation

CCWFGM_FWI::HourlyFFMC_Lawson	(	double	prev_std_ffmc,
		double	curr_std_ffmc,
		double	rain,
		double	temperature,
		double	rh,
		double	ws,
		unsigned long	seconds_into_day,
		double *	ffmc
	)

Calculates hourly FFMC (fine fuel moisture code), using Lawson's mathematical model, based on the previous and current daily FFMC values (using Van Wagner) and provided conditions. FFMC is a numerical rating of the moisture content of litter and other cured fine fuels.

Parameters

prev_std_ffmc	The previous day's standard daily Van Wagner FFMC value
curr_std_ffmc	The current day's standard daily Van Wagner FFMC value
rain	Precipitation, mm (ignored)
temperature	Celsius
rh	Relative humidity expressed as a fraction ([0..1])
ws	Wind speed (kph)
seconds_into_day	Local standard time
ffmc	Calculated FFMC value

See Also

ICWFGM_FWI::HourlyFFMC_Lawson

Return values

E_POINTER	The FFMC address provided is invalid
S_OK	Successful
E_INVALIDARG	Failure during calculation or if seconds_into_day is greater than 86400.

CCWFGM_FWI::HourlyFFMC_Lawson_Contiguous	(	double	in_ffmc_prevday,
		double	in_ffmc_currday,
		double	rain,
		double	temperature,
		double	rh_0,
		double	rh,
		double	rh_1,
		double	ws,
		unsigned long	seconds_into_day,
		double *	ffmc
	)

Calculates a contiguous hourly FFMC (fine fuel moisture code), using Lawson's mathematical model, based on the daily Van Wagner FFMC values for the previous and current days, as well as current provided conditions. FFMC is a numerical rating of the moisture content of litter and other cured fine fuels. This technique uses linear interpolation between 11am and noon LST. It also applies similar smoothing in morning hours.

Parameters

in_ffmc_prevday	The previous day's standard daily Van Wagner FFMC value
in_ffmc_currday	The current day's standard daily Van Wagner FFMC value
rain	Precipitation, mm (ignored)
temperature	Celsius
rh_0	Relative humidity at the start of the hour, expressed as a fraction ([0..1])
rh	Instantaneous relative humidity expressed as a fraction ([0..1])
rh_1	Relative humidity at the end of the hour (start of next hour) expressed as a fraction ([0..1])
ws	Wind speed (kph)
seconds_into_day	Local standard time
ffmc	Calculated FFMC value

See Also

ICWFGM_FWI::HourlyFFMC_Lawson_Contiguous

Return values

E_POINTER	The FFMC address provided is invalid
S_OK	Successful
E_INVALIDARG	Failure during calculation or if seconds_into_day is greater than 86400.

CCWFGM_FWI::HourlyFFMC_VanWagner	(	double	in_ffmc,
		double	rain,
		double	temperature,
		double	rh,
		double	ws,
		ULONG	seconds_since_ffmc,
		double *	ffmc
	)

Calculates hourly FFMC (fine fuel moisture code), using Van Wagner's mathematical model, based on the previous hour's FFMC and provided conditions. FFMC is a numerical rating of the moisture content of litter and other cured fine fuels.

Parameters

in_ffmc	The previous time's Van Wagner FFMC value
rain	Precipitation since observed FFMC, mm
temperature	Celsius
rh	Relative humidity expressed as a fraction ([0..1])
ws	Wind speed (kph)
seconds_since_ffmc	Seconds since observed FFMC
ffmc	Calculated FFMC value

See Also

ICWFGM_FWI::HourlyFFMC_VanWagner

Return values

E_POINTER	The FFMC address provided is invalid
S_OK	Successful
E_INVALIDARG	Failure during calculation, or the parameter seconds_since_ffmc is greater than 7200 seconds

CCWFGM_FWI::HourlyFFMC_VanWagner_Previous	(	double	current_ffmc,
		double	rain,
		double	temperature,
		double	rh,
		double	ws,
		double *	prev_ffmc
	)

Calculates the previous hourly FFMC (fine fuel moisture code), using Van Wagner's mathematical model, based on the current hour's FFMC and previous hour's provided conditions. FFMC is a numerical rating of the moisture content of litter and other cured fine fuels.

Parameters

current_ffmc	The current time's Van Wagner FFMC value
rain	Precipitation in the prior hour, mm
temperature	Celsius
rh	Relative humidity expressed as a fraction ([0..1])
ws	Wind speed (kph)
prev_ffmc	Calculated previous FFMC value

See Also

ICWFGM_FWI::HourlyFFMC_VanWagner_Previous

Return values

E_POINTER	The FFMC address provided is invalid
S_OK	Successful
E_INVALIDARG	Failure during calculation

CCWFGM_FWI::ISI_FBP	(	double	ffmc,
		double	ws,
		ULONG	seconds_since_ffmc,
		double *	isi
	)

Calculates ISI from FFMC and wind speed. ISI provides a numerical rating of the relative expected rate of fire spread. The FBP system uses a local site-specific ISI influenced by topography.

Parameters

ffmc	FFMC value
ws	Wind speed (kph)
seconds_since_ffmc	Seconds since observed ffmc
isi	Calculated ISI value

See Also

ICWFGM_FWI::ISI_FBP

CCWFGM_FWI::ISI_FWI

Return values

E_POINTER	The ISI address provided is invalid
S_OK	Successful
E_INVALIDARG	Failure during calculation

CCWFGM_FWI::ISI_FWI	(	double	ffmc,
		double	ws,
		ULONG	seconds_since_ffmc,
		double *	isi
	)

Calculates ISI from FFMC and wind speed. ISI provides a numerical rating of the relative expected rate of fire spread.

Parameters

ffmc	FFMC value
ws	Wind speed (kph)
seconds_since_ffmc	Seconds since observed ffmc
isi	Calculated ISI value

See Also

ICWFGM_FWI::ISI_FWI

CCWFGM_FWI::ISI_FBP

Return values

E_POINTER	The ISI address provided is invalid
S_OK	Successful
E_INVALIDARG	Failure during calculation