diff --git a/scripts/functions/position_count_bp.R b/scripts/functions/position_count_bp.R
index accc85a..b4699b6 100755
--- a/scripts/functions/position_count_bp.R
+++ b/scripts/functions/position_count_bp.R
@@ -40,6 +40,9 @@ site_snp_count_bp <- function (plotdf,
                                )
                                {
   
+  if (is.null(plotdf)){
+    return(ggplot() + annotate(x=1,y=1,"text", label="NO DATA")+theme_void())
+  }
   plotdf = as.data.frame(plotdf)
   # dim of plotdf
   cat(paste0("\noriginal df dimensions:"