I have a SpatialPointsDataFrame defining SD boundary, however when I compute the center with gCentroid it's shifted.
c. = rgeos::gCentroid(c.) %>% as.data.frame()
Why isn't it plotting it at the center?
Asked
Active
Viewed 167 times
0
Rafael
- 3,096
- 1
- 23
- 61
-
if you apply gCentroid to the bounding box does it still plot like that? – Elio Diaz Apr 09 '18 at 15:46
-
good idea, let me try – Rafael Apr 09 '18 at 15:47
-
however, the draw back of finding the centroid of the bounding box is that it won't be very well placed for 'strangely' shaped polygons – Rafael Apr 09 '18 at 16:02
1 Answers
2
It is because the mass of points is higher in the lower right corner. If you transform your object to a SpatialPolygons object (making it one shape) then it works:
poly <- SpatialPolygons(Srl = list(Polygons( srl = list(Polygon(coords = coordinates(dat))), ID = 1)))
gCentroid(spgeom = poly)
plot(poly)
axis(1)
axis(2)
points(gCentroid(poly))
Martin Schmelzer
- 23,283
- 6
- 73
- 98