pedometrics: Miscellaneous Pedometric Tools

# Extract spatial trend data
#
# @description
# Extract spatial trend data from an object of class \code{likfit}.
#
# @param x Object of class \code{likfit}.
#
# @details
# [pedometrics::trend.terms()] is similar to [stats::terms()]. [pedometrics::trend.matrix()] is
# similar to [stats::model.frame()]. Se also [geoR::likfit()].
# 
# @return 
#
# @author Alessandro Samuel-Rosa \email{alessandrosamuelrosa@@gmail.com}
# @aliases trend.terms trend.matrix
# FUNCTION - EXTRACT TREND TERMS ###############################################
# This function is similar to stats::terms
# @export
# @rdname trend
# trend.terms <-
#   function(x) {
#     # check if suggested packages are installed
#     if (!requireNamespace("geoR")) stop("geoR package is missing")
#     cl <- class(x)
#     if (all(cl == c("likGRF", "variomodel"))) {
#       res <- all.vars(x$trend)
#     }
#     return(res)
#   }
# FUNCTION - EXTRACT TREND MATRIX ##############################################
# This function is similar to stats::model.frame
# @export
# @rdname trend
# trend.matrix <-
#   function(x) {
#     # check if suggested packages are installed
#     if (!requireNamespace("geoR")) stop("geoR package is missing")
#     cl <- class(x)
#     if (all(cl == c("likGRF", "variomodel"))) {
#       res <- x$trend.matrix[, -1]
#       colnames(res) <- trend.terms(x)
#     }
#     return(res)
#   }