Merge pull request #87 from atsyplenkov/centerline

add centerline

Author: Nowosad

Spatial.md

@@ -405,6 +405,10 @@ Handling spatial data
 
 -   The `r pkg("areal")` package can be used to interpolate overlapping 
     but incongruent polygons, also known as areal weighted interpolation.
+-   The `r pkg("centerline")` package can be used for centerline (or median-axis) estimation of closed polygons,
+    such as lakes, landslides, or rivers. The package also
+    provides extensions to `r pkg("ggplot2")`, allowing users to place `geom_text` and `geom_label` at the center of a spatial
+    polygon, which can be useful for map-making.
 -   The `r pkg("qualmap")` package can be used to digitize qualitative GIS data.
 -   The `r pkg("exactextractr")` for fast and accurate summary of raster values
     on polygonal areas (known as zonal statistics).