From 5d4fcc8d40ec44d68f73cbae3e7e55e63254953b Mon Sep 17 00:00:00 2001
From: Mathew Sutcliffe <oktal3700@gmail.com>
Date: Sun, 18 Aug 2013 17:29:37 +0100
Subject: [PATCH] resolved pressure constants 1013.2hPa != 29.92inHg

---
 src/blackmisc/pqconstants.h                | 24 ++++++++++++++++++++--
 src/blackmisc/pqunits.h                    | 13 +-----------
 tests/blackmisc/testphysicalquantities.cpp |  4 +---
 3 files changed, 24 insertions(+), 17 deletions(-)

diff --git a/src/blackmisc/pqconstants.h b/src/blackmisc/pqconstants.h
index 173a605ae..d2a7ce937 100644
--- a/src/blackmisc/pqconstants.h
+++ b/src/blackmisc/pqconstants.h
@@ -40,15 +40,35 @@ public:
     }
 
     /*!
-     * \brief Standard pressure 1013,25mbar / 29.92inHg
+     * \brief International Standard Atmosphere pressure at mean sea level, 1013.25hPa
      * \return
      */
-    static const CPressure& InternationalStandardSeaLevelPressure()
+    static const CPressure& ISASeaLevelPressure()
     {
         static CPressure p(1013.25, CPressureUnit::hPa());
         return p;
     }
 
+    /*!
+     * \brief ICAO standard pressure datum for flight levels, 1013.2hPa
+     * \return
+     */
+    static const CPressure& ICAOFlightLevelPressure()
+    {
+        static CPressure p(1013.2, CPressureUnit::hPa());
+        return p;
+    }
+
+    /*!
+     * \brief Standard pressure datum for flight levels in USA, Canada, parts of Latin America, 29.92inHg
+     * \return
+     */
+    static const CPressure& USFlightLevelPressure()
+    {
+        static CPressure p(29.92, CPressureUnit::inHg());
+        return p;
+    }
+
     /*!
      * \brief Unicom frequency
      * \return
diff --git a/src/blackmisc/pqunits.h b/src/blackmisc/pqunits.h
index c20c0771e..a6c355580 100644
--- a/src/blackmisc/pqunits.h
+++ b/src/blackmisc/pqunits.h
@@ -627,17 +627,7 @@ public:
      */
     static const CPressureUnit &inHg()
     {
-        static CPressureUnit inhg(QT_TRANSLATE_NOOP("CMeasurementUnit", "inch of mercury 0C"), "inHg", false, 3386.389);
-        return inhg;
-    }
-
-    /*!
-     * \brief Inch of mercury for flight level 29,92inHg = 1013,25mbar = 1013,25hPa
-     * \return
-     */
-    static const CPressureUnit &inHgFL()
-    {
-        static CPressureUnit inhg(QT_TRANSLATE_NOOP("CMeasurementUnit", "inch of mercury"), "inHg", false, 3386.5307486631);
+        static CPressureUnit inhg(QT_TRANSLATE_NOOP("CMeasurementUnit", "inch of mercury"), "inHg", false, 3386.389);
         return inhg;
     }
 
@@ -653,7 +643,6 @@ public:
             u.append(CPressureUnit::bar());
             u.append(CPressureUnit::hPa());
             u.append(CPressureUnit::inHg());
-            u.append(CPressureUnit::inHgFL());
             u.append(CPressureUnit::mbar());
             u.append(CPressureUnit::psi());
         }
diff --git a/tests/blackmisc/testphysicalquantities.cpp b/tests/blackmisc/testphysicalquantities.cpp
index 9b9202b3e..2a918a458 100644
--- a/tests/blackmisc/testphysicalquantities.cpp
+++ b/tests/blackmisc/testphysicalquantities.cpp
@@ -122,13 +122,11 @@ void CTestPhysicalQuantities::pressureTests()
 {
     CPressure p1(1013.25, CPressureUnit::hPa());
     CPressure p2(29.92, CPressureUnit::inHg());
-    CPressure p3(29.92, CPressureUnit::inHgFL());
     CPressure p4(p1);
     p4.switchUnit(CPressureUnit::mbar());
 
     // does not match exactly
     QVERIFY2(p1 != p2, "Standard pressure test little difference");
-    QVERIFY2(p1 == p3, "Standard pressure test matching");
     QVERIFY2(p1.unitValueToDouble() == p4.unitValueToDouble(), "mbar/hPa test");
 }
 
@@ -195,7 +193,7 @@ void CTestPhysicalQuantities::memoryTests()
  */
 void CTestPhysicalQuantities::basicArithmetic()
 {
-    CPressure p1 = CPhysicalQuantitiesConstants::InternationalStandardSeaLevelPressure();
+    CPressure p1 = CPhysicalQuantitiesConstants::ISASeaLevelPressure();
     CPressure p2(p1);
     p2 *= 2.0;
     CPressure p3 = p1 + p1;