Volume and phytomass functions are tabulated in Tabacchi et al. (2011a).
The tabulation covers a limited region of the dbh by h_tot rectangle.
This region is the "domain" of the reliable estimates, based on the
distribution of the sample trees used to calibrate the functions.
The coefficient of variation (CV = standard_deviation / estimate) is computed
and plotted (as 'filled contours') for the whole rectangular area,
the limits of the region of reliable estimates (the "domain"), is
superimposed as a light colored line. Function output is a ggplot object that can be used
by its self or as a background on top of which the user can plot his/her data to
verify eventual accuracy or reliability problems.
Two functions are available.
INFCaccuracyPlot() - allows the plots to be fully customized but, beware,
all values required for the 'fill' will be computed and,
at finer resolution, the process can be slow.
INFCaccuracyPlot0() - produces, much faster, the plots at the finest
resolution, using pre-calculated values stored in
a specific auxiliary dataframe (see INFC_CVgrid),
necessarily leaving less customization freedom.
(** compute_grid0() - is an internal function exported for the sake of
the Populate_INFC_CVgrid() function **)
INFCaccuracyPlot(
EPPOcod,
quantity = "vol",
ie.Var = FALSE,
cv.ul = 0.1,
fixed = TRUE,
plot.est = FALSE,
dbh.step = 5,
htot.step = dbh.step,
dbh.buf = 1,
htot.buf = dbh.buf
)INFCaccuracyPlot0(
EPPOcod,
quantity = "vol",
ie.Var = FALSE,
cv.ul = 0.1,
fixed = TRUE,
plot.est = FALSE
)
compute_grid0(pag, EPPOcod, quantity)
INFCaccuracyPlot The function returns a ggplot object.
A string, one of the EPPO tree species codes listed in
INFCspecies table (Reference: https://gd.eppo.int )
(optional) A string specifying the quantity to be estimated,
one of c("vol", "dw1" : "dw4").
Lookup Qantities table to retrieve codes definitions.
Defaults to "vol".
(optional) Logical. Choose variance estimator:
TRUE = variance for an 'individual estimate'
FALSE = variance for the 'estimate of an average' value
Default ie.Va = FALSE
(optional) Numeric. Cutoff CV level for the plot. Defaults to 0.1
(optional) Logical. Contour plot breaks:
TRUE = break levels are fixed
FALSE = breaks are tailored to the specific case
(in order to split the values within the range of interest [0, cv.ul],
into equally numerous bins)
Default fixed = TRUE
(optional) Logical. Add the 'estimated quantity' layer as
contour lines. Default plot.est = FALSE
(optional) Numeric. Computation with smaller step produces a
plot with better resolution but increases consistently computation time
(see INFCaccuracyPlot0()). To reduce computation time, the step
defaults to 5.
(optional) Numeric. As for dbh.
(optional) Numeric. Extra space in the plot beyond the 'domain'. Default: 1
(optional) Numeric. As for dbh.
for the internal function compute_grid0()