From b84c36c91ab49ec69a9fc28cc165b78fb73a77e3 Mon Sep 17 00:00:00 2001
From: AdenKoperczak <awkoperczak@gmail.com>
Date: Sat, 3 May 2025 10:14:53 -0400
Subject: [PATCH] Add GetRadarBeamAltititude into geographic lib

---
 .../source/scwx/qt/util/geographic_lib.cpp    | 20 +++++++++++++++++++
 .../source/scwx/qt/util/geographic_lib.hpp    | 15 ++++++++++++++
 2 files changed, 35 insertions(+)

diff --git a/scwx-qt/source/scwx/qt/util/geographic_lib.cpp b/scwx-qt/source/scwx/qt/util/geographic_lib.cpp
index bfaf408f..8181f34c 100644
--- a/scwx-qt/source/scwx/qt/util/geographic_lib.cpp
+++ b/scwx-qt/source/scwx/qt/util/geographic_lib.cpp
@@ -2,6 +2,7 @@
 #include <scwx/util/logger.hpp>
 
 #include <numbers>
+#include <cmath>
 
 #include <GeographicLib/Gnomonic.hpp>
 #include <geos/algorithm/PointLocation.h>
@@ -289,6 +290,25 @@ bool AreaInRangeOfPoint(const std::vector<common::Coordinate>& area,
     return GetDistanceAreaPoint(area, point) <= distance;
 }
 
+units::length::meters<double>
+GetRadarBeamAltititude(units::length::meters<double> range,
+                       units::angle::degrees<double> elevation,
+                       units::length::meters<double> height)
+{
+   static const units::length::meters<double> earthRadius {6367444 * 4/3};
+
+   height += earthRadius;
+
+   const double elevationRadians =
+      units::angle::radians<double>(elevation).value();
+   const auto altitudeSquared =
+      (range * range + height * height +
+       2 * range * height * std::sin(elevationRadians));
+
+   return units::length::meters<double>(std::sqrt(altitudeSquared.value())) -
+          earthRadius;
+}
+
 } // namespace GeographicLib
 } // namespace util
 } // namespace qt
diff --git a/scwx-qt/source/scwx/qt/util/geographic_lib.hpp b/scwx-qt/source/scwx/qt/util/geographic_lib.hpp
index 5038d9a9..1d6cc38e 100644
--- a/scwx-qt/source/scwx/qt/util/geographic_lib.hpp
+++ b/scwx-qt/source/scwx/qt/util/geographic_lib.hpp
@@ -121,6 +121,21 @@ bool AreaInRangeOfPoint(const std::vector<common::Coordinate>& area,
                         const common::Coordinate&              point,
                         const units::length::meters<double>    distance);
 
+/**
+ * Get the altitude of the radar beam at a given distance, elevation and height
+ *
+ * @param [in] range The range to the radar site
+ * @param [in] elevation The elevation of the radar site
+ * @param [in] height The height of the radar site
+ *
+ * @return The altitude of the radar at that range
+ */
+units::length::meters<double>
+GetRadarBeamAltititude(units::length::meters<double> range,
+                       units::angle::degrees<double> elevation,
+                       units::length::meters<double> height);
+
+
 } // namespace GeographicLib
 } // namespace util
 } // namespace qt