diff --git a/cdm/core/src/main/java/ucar/unidata/geoloc/LatLonPoints.java b/cdm/core/src/main/java/ucar/unidata/geoloc/LatLonPoints.java
index 2beea32c26..657aebaf67 100644
--- a/cdm/core/src/main/java/ucar/unidata/geoloc/LatLonPoints.java
+++ b/cdm/core/src/main/java/ucar/unidata/geoloc/LatLonPoints.java
@@ -1,7 +1,8 @@
 /*
- * Copyright (c) 1998-2020 John Caron and University Corporation for Atmospheric Research/Unidata
+ * Copyright (c) 1998-2025 John Caron and University Corporation for Atmospheric Research/Unidata
  * See LICENSE for license information.
  */
+
 package ucar.unidata.geoloc;
 
 import java.util.Formatter;
@@ -77,7 +78,7 @@ public static double lonNormalFrom(double lon, double start) {
   /**
    * Normalize the longitude to lie between +/-180
    *
-   * @param lon east latitude in degrees
+   * @param lon east longitude in degrees
    * @return normalized lon
    */
   public static double lonNormal(double lon) {
diff --git a/cdm/core/src/test/java/ucar/unidata/geoloc/TestLatLonProjection.java b/cdm/core/src/test/java/ucar/unidata/geoloc/TestLatLonProjection.java
index 20fc82221b..cb039697b3 100644
--- a/cdm/core/src/test/java/ucar/unidata/geoloc/TestLatLonProjection.java
+++ b/cdm/core/src/test/java/ucar/unidata/geoloc/TestLatLonProjection.java
@@ -1,29 +1,28 @@
 /*
- * Copyright (c) 1998-2018 University Corporation for Atmospheric Research/Unidata
+ * Copyright (c) 1998-2025 University Corporation for Atmospheric Research/Unidata
  * See LICENSE for license information.
  */
+
 package ucar.unidata.geoloc;
 
 import org.junit.Assert;
+import org.junit.Before;
+import org.junit.Test;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import ucar.unidata.geoloc.projection.*;
-import junit.framework.*;
 import java.lang.invoke.MethodHandles;
 
 /**
  *
  * @author John Caron
  */
-public class TestLatLonProjection extends TestCase {
+public class TestLatLonProjection {
   private static final Logger logger = LoggerFactory.getLogger(MethodHandles.lookup().lookupClass());
 
   private LatLonProjection p;
 
-  public TestLatLonProjection(String name) {
-    super(name);
-  }
-
+  @Before
   public void setUp() {
     p = new LatLonProjection();
   }
@@ -66,6 +65,7 @@ void runCenter(double center) {
     }
   }
 
+  @Test
   public void testLatLonToProjBB() {
     runCenter();
     runCenter(110.45454545454547);
@@ -82,6 +82,7 @@ public LatLonRect testIntersection(LatLonRect bbox, LatLonRect bbox2) {
     return result;
   }
 
+  @Test
   public void testIntersection() {
     LatLonRect bbox = new LatLonRect(LatLonPoint.create(40.0, -100.0), 10.0, 20.0);
     LatLonRect bbox2 = new LatLonRect(LatLonPoint.create(-40.0, -180.0), 120.0, 300.0);
@@ -108,6 +109,7 @@ private LatLonRect testExtend(LatLonRect bbox, LatLonRect bbox2) {
     return bbox;
   }
 
+  @Test
   public void testExtend() {
     LatLonRect bbox;
 
diff --git a/grib/src/main/java/ucar/nc2/grib/grib1/Grib1Gds.java b/grib/src/main/java/ucar/nc2/grib/grib1/Grib1Gds.java
index 66cb6319c3..102f8dd7fa 100644
--- a/grib/src/main/java/ucar/nc2/grib/grib1/Grib1Gds.java
+++ b/grib/src/main/java/ucar/nc2/grib/grib1/Grib1Gds.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1998-2018 John Caron and University Corporation for Atmospheric Research/Unidata
+ * Copyright (c) 1998-2025 John Caron and University Corporation for Atmospheric Research/Unidata
  * See LICENSE for license information.
  */
 
@@ -556,6 +556,9 @@ public String toString() {
     @Override
     public GdsHorizCoordSys makeHorizCoordSys() {
       LatLonProjection proj = new LatLonProjection(getEarth());
+      double centerLon = ((int) ((lo2 - lo1 + deltaLon) / 2 / scale3)) * scale3;
+      proj.setCenterLon(centerLon);
+
       // ProjectionPoint startP = proj.latLonToProj(LatLonPoint.create(la1, lo1));
       double startx = lo1; // startP.getX();
       double starty = la1; // startP.getY();
diff --git a/grib/src/main/java/ucar/nc2/grib/grib2/Grib2Gds.java b/grib/src/main/java/ucar/nc2/grib/grib2/Grib2Gds.java
index 27117448fd..3550412711 100644
--- a/grib/src/main/java/ucar/nc2/grib/grib2/Grib2Gds.java
+++ b/grib/src/main/java/ucar/nc2/grib/grib2/Grib2Gds.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1998-2018 John Caron and University Corporation for Atmospheric Research/Unidata
+ * Copyright (c) 1998-2025 John Caron and University Corporation for Atmospheric Research/Unidata
  * See LICENSE for license information.
  */
 
@@ -518,6 +518,8 @@ public int[] getOptionalPoints() {
 
     public GdsHorizCoordSys makeHorizCoordSys() {
       LatLonProjection proj = new LatLonProjection(getEarth());
+      double centerLon = ((int) ((lo2 - lo1 + deltaLon) / 2 / getScale())) * getScale();
+      proj.setCenterLon(centerLon);
       // ProjectionPoint startP = proj.latLonToProj(LatLonPoint.create(la1, lo1));
       double startx = lo1; // startP.getX();
       double starty = la1; // startP.getY();