feat: area()

DESCRIPTION

@@ -106,6 +106,7 @@ Collate:
     'methods-IDs.R'
     'methods-XY.R'
     'methods-affine.R'
+    'methods-area.R'
     'methods-centroids.R'
     'methods-coerce.R'
     'methods-convHull.R'

NAMESPACE

@@ -308,6 +308,7 @@ exportMethods(XY)
 exportMethods(activeFeatType)
 exportMethods(activeSpatUnit)
 exportMethods(affine)
+exportMethods(area)
 exportMethods(as.character)
 exportMethods(as.list)
 exportMethods(as.matrix)

R/generics.R

@@ -84,12 +84,13 @@ setGeneric(
     function(x, ...) standardGeneric("overlapToMatrix")
 )
 
-# Methods and documentations found in methods-spatShift.R
+
 setGeneric("spatShift", function(x, ...) standardGeneric("spatShift"))
 setGeneric("affine", function(x, y, ...) standardGeneric("affine"))
 setGeneric("shear", function(x, ...) standardGeneric("shear"))
 setGeneric("XY", function(x, ...) standardGeneric("XY"))
 setGeneric("XY<-", function(x, ..., value) standardGeneric("XY<-"))
+setGeneric("area", function(x, ...) standardGeneric("area"))
 
 # Methods and documentations found in methods-overlaps.R
 setGeneric("overlaps", function(x, ...) standardGeneric("overlaps"))

R/methods-area.R

@@ -0,0 +1,36 @@
+# docs ----------------------------------------------------------- #
+#' @title Get the area of individual polygons
+#' @name area
+#' @description Compute the area covered by polygons
+#' @param x `giottoPolygon`
+#' @param ... additional args to pass
+#' @returns `numeric` vector of spatial area
+#' @examples
+#' sl <- GiottoData::loadSubObjectMini("spatLocsObj")
+#' gpoly <- GiottoData::loadSubObjectMini("giottoPolygon")
+#' gpoints <- GiottoData::loadSubObjectMini("giottoPoints")
+#' 
+#' # area of polygons
+#' area(gpoly)
+#' 
+#' # area of the convex hull
+#' area(convHull(sl))
+#' feature_hulls <- convHull(gpoints, by = "feat_ID")
+#' area(feature_hulls)
+#'
+NULL
+# ---------------------------------------------------------------- #
+
+#' @rdname area
+#' @export
+setMethod("area", signature("giottoPolygon"), function(x, ...) {
+    # handle warning about missing CRS
+    handle_warnings(area(x[], ...))$result
+})
+
+#' @rdname area
+#' @export
+setMethod("area", signature("SpatVector"), function(x, ...) {
+    # handle warning about missing CRS
+    handle_warnings(terra::expanse(x, transform = FALSE, ...))$result
+})