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The .slf File

The slfReader function parses the .slf file and stores the data in the standInfoArray variable. Each set of stand information in the .slf file is composed of four records. Each record is designated with an A, B, C or D in the file. The program, therefore, has four different data types to hold each record type. The data types are called StandInfo_A, StandInfo_B, StandInfo_C and StandInfo_D where each holds its respective designated record. Every set of these records along with the stand's identifier is stored in a StandInfo structure. The standInfoArray is simply an array of pointers to StandInfo structures along with a count of how many items are stored in the array.

The format of an A-record in the .slf file is:

Never	Data	Field	Purpose
Used	Type	Name
X	char *	fvsFName	The name of the file in FVS that generated the .slf file.
X	char *	dataFlag	It's not clear what this field is. The value NoPointData is found here.
X	Node *	variants	A linked list of strings (strings' length is at most 2.)

The format of a B-record in the .slf file is:

Never	Data	Field	Purpose
Used	Type	Name
	int	inventoryYear
	int	latitude
	int	longitude
X	char *	locationCode
X	char *	habitatType
	int	originYear
	int	aspect	aspect in degrees
	int	slope	percentage
	int	elevation	elevation in hundreds of feet
	float	basalAreaFactor	a negative value is read as inverse of large-tree fixed plot
			size in acres
	float	inversePlotSize	inverse of fixed plot size in acres
X	float	breakPtDBH	in inches
X	int	numOfPlots
X	int	numOfNSPlots	number of non-stockable plots
X	float	sampleWeight	stand sampling weight or size (usually acres) used to
			compute weighted average yield tables and other weighted
			averages among some set of stands.
	int	stockable	stockable percent.
X	char *	diaTransCode	diameter growth translation code as defined for FVS
X	int	diaMeasurePd	diameter growth measurement period (in years)
X	char *	htTransCode	height growth translation code as defined for FVS
X	int	htMeasurePd	height growth measurement period (in years)
X	int	mortalMeasurePd	mortality measurement period (in years)
	float	maxBasalArea	maximum basal area
	int	maxDensityIndex	maximum stand density index
	int	species	site species code
	int	index	site index
X	int	type	modes type code
	int	region	physiographic region code
	int	forestType	forest type code

The format of a C-record in the .slf file is:

Never	Data	Field	Purpose
Used	Type	Name
X	char **	key
X	char **	value
	int	count	The number of key-value pairs

The C-record is clearly a dictionary. The dictionary is never used, however.

The format of a D-record in the .slf file is:

Never	Data	Field	Purpose
Used	Type	Name
X	char **	addFile
	int	count	The number of files in the array

The StandInfo* structures are all used solely as an interface to the .slf file (really only the StandInfo_B structure is used.) The data in these structures is used to populate the stands variable in standInterface.c. The stands variable is then used for the data abstractions for the application. Note that the stands variable is not populated until after the .stnd file is read (see Section 4.2.5). The parsing of the .slf file only creates the StandInfo* structures that are used as the file interface. With that understanding, the table below is presented here for completeness.

stands[] Field Name	Initialized by StandInfo_B Field
(Application Abstraction)	(File Interface)
inventoryYear	inventoryYear
origin_year	originYear
aspect	aspect
slope	slope
elevation	elevation
app	inversePlotSize
stockable	stockable
max_basal_area	maxBasalArea
density	maxDensityIndex
site	species
index	index
physiographic_region	region
forest_type	forestType