geographical pattern causality

Usage

# S4 method for class 'sf'
gpc(
  data,
  cause,
  effect,
  libsizes = NULL,
  E = 3,
  k = E + 2,
  tau = 1,
  style = 1,
  lib = NULL,
  pred = NULL,
  boot = 99,
  random = TRUE,
  seed = 42L,
  dist.metric = "L2",
  zero.tolerance = k,
  relative = TRUE,
  weighted = TRUE,
  threads = detectThreads(),
  detrend = FALSE,
  parallel.level = "low",
  bidirectional = TRUE,
  progressbar = TRUE,
  nb = NULL
)

# S4 method for class 'SpatRaster'
gpc(
  data,
  cause,
  effect,
  libsizes = NULL,
  E = 3,
  k = E + 2,
  tau = 1,
  style = 1,
  lib = NULL,
  pred = NULL,
  boot = 99,
  random = TRUE,
  seed = 42L,
  dist.metric = "L2",
  zero.tolerance = k,
  relative = TRUE,
  weighted = TRUE,
  threads = detectThreads(),
  detrend = FALSE,
  parallel.level = "low",
  bidirectional = TRUE,
  progressbar = TRUE,
  grid.coord = TRUE
)

Arguments

data: observation data.
cause: name of causal variable.
effect: name of effect variable.
libsizes: (optional) number of spatial units used (input needed: vector - spatial vector, matrix - spatial raster).
E: (optional) embedding dimensions.
k: (optional) number of nearest neighbors.
tau: (optional) step of spatial lags.
style: (optional) embedding style (0 includes current state, 1 excludes it).
lib: (optional) libraries indices (input requirement same as libsizes).
pred: (optional) predictions indices (input requirement same as libsizes).
boot: (optional) number of bootstraps to perform.
random: (optional) whether to use random sampling.
seed: (optional) random seed.
dist.metric: (optional) distance metric (L1: Manhattan, L2: Euclidean).
zero.tolerance: (optional) maximum number of zeros tolerated in signature space.
relative: (optional) whether to calculate relative changes in embeddings.
weighted: (optional) whether to weight causal strength.
threads: (optional) number of threads to use.
detrend: (optional) whether to remove the linear trend.
parallel.level: (optional) level of parallelism, low or high.
bidirectional: (optional) whether to examine bidirectional causality.
progressbar: (optional) whether to show the progress bar.
nb: (optional) neighbours list.
grid.coord: (optional) whether to detrend using cell center coordinates (TRUE) or row/column numbers (FALSE).

Value

A list

xmap: cross mapping results (only present if libsizes is not NULL)
causality: per-sample causality statistics (present if libsizes is NULL)
summary: overall causal strength (present if libsizes is NULL)
pattern: pairwise pattern relationships (present if libsizes is NULL)
varname: names of causal and effect variables
bidirectional: whether to examine bidirectional causality

References

Zhang, Z., Wang, J., 2025. A model to identify causality for geographic patterns. International Journal of Geographical Information Science 1–21.

Examples

columbus = sf::read_sf(system.file("case/columbus.gpkg",package="spEDM"))
# \donttest{
gpc(columbus,"hoval","crime",E = 6,k = 9)
#> -------------------------------- 
#> ***pattern causality analysis*** 
#> -------------------------------- 
#>       type  strength      direction
#> 1 positive       NaN hoval -> crime
#> 2 negative 0.1340069 hoval -> crime
#> 3     dark 0.1043991 hoval -> crime
#> 4 positive       NaN crime -> hoval
#> 5 negative 0.6251773 crime -> hoval
#> 6     dark 0.1468990 crime -> hoval

# convergence diagnostics
g = gpc(columbus,"hoval","crime",libsizes = seq(5,45,5),E = 6,k = 9)
#> 
Computing: [========================================] 100% (done)                         
#> 
Computing: [========================================] 100% (done)                         
plot(g)

# }