From e3d86f09801bebdc9879a9f398153d776e138424 Mon Sep 17 00:00:00 2001
From: Wen Meng <wen.meng@noaa.gov>
Date: Fri, 17 Jan 2020 00:25:06 +0000
Subject: [PATCH] Add capacity of detecting scaning mode north2south vs
 south2north in gaussian grid from Dusan.

---
 sorc/ncep_post.fd/grib2_module.f | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/sorc/ncep_post.fd/grib2_module.f b/sorc/ncep_post.fd/grib2_module.f
index 134058ab0..2c6fce6f5 100644
--- a/sorc/ncep_post.fd/grib2_module.f
+++ b/sorc/ncep_post.fd/grib2_module.f
@@ -1394,6 +1394,11 @@ subroutine getgds(ldfgrd,len3,ifield3len,igds,ifield3)
        ifield3(16) = lonlast 
        ifield3(17) = NINT(360./(IM)*1000000.)
        ifield3(18) = NINT(JM/2.0)
+       if( latstart < latlast ) then
+        ifield3(19) = 64      !for SN scan
+       else
+        ifield3(19) = 0       !for NS scan
+       endif
 !
 !** Latlon grid
       ELSE IF(MAPTYPE == 0 ) THEN