diff --git a/R/generate_poly.R b/R/generate_poly.R
index 6edce56b..106a970e 100644
--- a/R/generate_poly.R
+++ b/R/generate_poly.R
@@ -29,9 +29,22 @@ polyStamp <- function(stamp_dt,
     stop(wrap_txt('Not all colnames found in spatlocs'))
   }
 
-  # define polys relative to centroid
-  stamp_centroid = c(x = mean(stamp_dt[['x']]),
-                     y = mean(stamp_dt[['y']]))
+  # define polys relative to centroid of stamp_dt
+  # add necessary columns to make a polygon from matrix
+  stamp_dt$geom = 1
+  stamp_dt$part = 0
+  stamp_dt$hole = 0
+
+  data.table::setcolorder(stamp_dt, neworder = c("geom", "part", "x", "y", "hole"))
+  stamp_poly = terra::vect(as.matrix(stamp_dt), type = "polygons")
+
+  centroid_dt = data.table::as.data.table(terra::centroids(stamp_poly),
+                              geom = "XY",
+                              include_values = F)
+  
+  stamp_centroid = c(x = centroid_dt$x,
+                     y = centroid_dt$y)
+
   rel_vertices = data.table::data.table(x = stamp_dt$x - stamp_centroid[['x']],
                                         y = stamp_dt$y - stamp_centroid[['y']])