I am wanting to create a mask to color all parts of the image that are NOT within the specified land areas. I can get this to work successfully for two countries (e.g Burkina Faso and Nigeria). However, the same code does not work when I try a longer list of 9 countries in the same area. The error I am receiving is : Error in [[<-.data.frame(tmp, attr(x, "sf_column"), value = list( : replacement has 2 rows, data has 1

Being relatively new to GIS, I am not quite sure what the issue is or how to resolve it. I would really appreciate some help if people could offer some insight. The method I used was based on the accepted answer from