As part of a larger problem (adding a ,makeUniqueIDs argument to rbind.SpatialPolygonsDataFrame for situations when the polygon IDs are identical),
,makeUniqueIDs
rbind.SpatialPolygonsDataFrame
rbind() needs the two object names to be the same. For example, the first object names: ID Age, the next object names: ID Gender,if you want to use rbind(), it will print out:
rbind()
ID Age
ID Gender
names do not match previous names