diff --git a/importPicture/src/osm/jp/gpx/ImportPicture.java b/importPicture/src/osm/jp/gpx/ImportPicture.java
index b14ad5b..f4d2ea8 100644
--- a/importPicture/src/osm/jp/gpx/ImportPicture.java
+++ b/importPicture/src/osm/jp/gpx/ImportPicture.java
@@ -592,9 +592,10 @@
                                 Double r = Math.cos(Math.toRadians((imaLAT + maeLAT) * 2)) * R;
                                 Double x = Math.toRadians(imaLON - maeLON) * r;
                                 Double y = Math.toRadians(imaLAT - maeLAT) * R;
-                                Double rad = Math.tan(a).toDegrees(x / y);
+                                double rad = Math.toDegrees(Math.atan(y / x));
+                                System.out.println("magvar = " + rad);
                                 magvar = ret.getOwnerDocument().createElement("magvar");
-                                magvar.setTextContent(rad.toString());
+                                magvar.setTextContent(Double.toString(rad));
                                 ret.appendChild(magvar);
                             }
                         }