I am trying to extract the mean of a raster data to polygons with the following code:


regions <- readShapeSpatial("Regions.shp") #SpatialPolygonsDataFrame

plot(regions, add=T)

enter image description here

regions@data = data.frame(regions@data, polygon_agri_suitability)


After data.frame I get an error:

arguments imply differing number of rows:1549, 0

My "Regions.shp" file in fact includes 1549 rows. But I don't know what this error means and how I can solve it.

  • polygon_agri_suitability turns a csv file including variables from the polygon layer but nothing from raster data.
    – D_B
    Jun 9, 2018 at 22:14
  • I don't understand rest of your questions. But the code works with other polygon layers, and I don't understand what's different about this specific polygon layer ("Regions.shp").
    – D_B
    Jun 9, 2018 at 22:15
  • what do you mean by "clip with SpatialPolygons object"? where in the code you are referring to? what's the code?
    – D_B
    Jun 9, 2018 at 22:16
  • Let us continue this discussion in chat. Jun 9, 2018 at 22:21

1 Answer 1


Thanks to @AndreSilva, I found the problem and the solution.

The problem was that the polygon and raster layers had different geographic systems. So I used Data Management Project tool of ArcMap to get both layers in WGS 1984. Now, the polygon layer exactly overlaps with the raster map, and the code works correctly.

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