Empirical variogram
s_variogram.Rd
Computes the empirical variogram using “bins” of distance provided by the user.
Usage
s_variogram(
data,
variable,
bins = NULL,
n_permutation = 0,
convert_to_utm = TRUE,
scale_to_km = FALSE
)
Arguments
- data
an object of class
sf
containing the variable for which the variogram is to be computed and the coordinates- variable
a character indicating the name of variable for which the variogram is to be computed.
- bins
a vector indicating the `bins` to be used to define the classes of distance used in the computation of the variogram. By default
bins=NULL
and bins are then computed asseq(0, d_max/2, length=15)
whered_max
is the maximum distance observed in the data.- n_permutation
a non-negative integer indicating the number of permutation used to compute the 95 level envelope under the assumption of spatial independence. By default
n_permutation=0
, and no envelope is generated.- convert_to_utm
a logical value, indicating if the conversion to UTM shuold be performed (
convert_to_utm = TRUE
) or the coordinate reference system of the data must be used without any conversion (convert_to_utm = FALSE
). By defaultconvert_to_utm = TRUE
. Note: ifconvert_to_utm = TRUE
the conversion to UTM is performed using the epsg provided bypropose_utm
.- scale_to_km
a logical value, indicating if the distances used in the variogram must be scaled to kilometers (
scale_to_km = TRUE
) or left in meters (scale_to_km = FALSE
). By defaultscale_to_km = FALSE
Value
an object of class 'variogram' which is a list containing the following components
variogram
a data-frame containing the following columns: mid_points
,
the middle points of the classes of distance provided by bins
;
obs_vari
the values of the observed variogram; obs_vari
the number of pairs.
If n_permutation > 0
, the data-frame also contains lower_bound
and upper_bound
corresponding to the lower and upper bounds of the 95
used to assess the departure of the observed variogram from the assumption of spatial independence.
scale_to_km
the value passed to scale_to_km
n_permutation
the number of permutations