sum_edc: Calculate isotropic Sum of Exponentially Decaying...

In amadeus: Accessing and Analyzing Large-Scale Environmental Data

Calculate isotropic Sum of Exponentially Decaying Contributions (SEDC) covariates

Description

Calculate isotropic Sum of Exponentially Decaying Contributions (SEDC) covariates

Usage

sum_edc(
  from = NULL,
  locs = NULL,
  locs_id = NULL,
  sedc_bandwidth = NULL,
  target_fields = NULL,
  geom = FALSE
)

Arguments

from	SpatVector(1). Point locations which contain point-source covariate data.
locs	sf/SpatVector(1). Locations where the sum of exponentially decaying contributions are calculated.
locs_id	character(1). Name of the unique id field in point_to.
sedc_bandwidth	numeric(1). Distance at which the source concentration is reduced to exp(-3) (approximately -95 %)
target_fields	character(varying). Field names in characters.
geom	FALSE/"sf"/"terra".. Should the function return with geometry? Default is FALSE, options with geometry are "sf" or "terra". The coordinate reference system of the sf or SpatVector is that of from.

Value

a data.frame (tibble) or SpatVector object with input field names with a suffix "_sedc" where the sums of EDC are stored. Additional attributes are attached for the EDC information.

• 'attr(result, "sedc_bandwidth")“: the bandwidth where concentration reduces to approximately five percent

• 'attr(result, "sedc_threshold")“: the threshold distance at which emission source points are excluded beyond that

Note

The function is originally from chopin Distance calculation is done with terra functions internally. Thus, the function internally converts sf objects in point_* arguments to terra. The threshold should be carefully chosen by users.

Author(s)

Insang Song

References

\insertRef

messier2012integratingamadeus

\insertRef

web_sedctutorial_packageamadeus

Examples

set.seed(101)
ncpath <- system.file("gpkg/nc.gpkg", package = "sf")
nc <- terra::vect(ncpath)
nc <- terra::project(nc, "EPSG:5070")
pnt_locs <- terra::centroids(nc, inside = TRUE)
pnt_locs <- pnt_locs[, "NAME"]
pnt_from <- terra::spatSample(nc, 10L)
pnt_from$pid <- seq(1, 10)
pnt_from <- pnt_from[, "pid"]
pnt_from$val1 <- rgamma(10L, 1, 0.05)
pnt_from$val2 <- rgamma(10L, 2, 1)

vals <- c("val1", "val2")
sum_edc(pnt_locs, pnt_from, "NAME", 1e4, vals)

amadeus documentation built on April 4, 2025, 12:21 a.m.