From ad10470eb177d56a687e032831cee65ab5a279aa Mon Sep 17 00:00:00 2001
From: Klaus Basan <klaus.basan@klausbasan.de>
Date: Sat, 28 Apr 2018 19:04:06 +0200
Subject: [PATCH] Ref T261, improved "finding" for elevation, "findFirst" for
 small radius

---
 src/blackmisc/geo/geoobjectlist.cpp                      | 9 +++++++++
 src/blackmisc/geo/geoobjectlist.h                        | 3 +++
 .../simulation/simulationenvironmentprovider.cpp         | 8 ++++++--
 3 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/src/blackmisc/geo/geoobjectlist.cpp b/src/blackmisc/geo/geoobjectlist.cpp
index eecc9c8c4..3321e7910 100644
--- a/src/blackmisc/geo/geoobjectlist.cpp
+++ b/src/blackmisc/geo/geoobjectlist.cpp
@@ -53,6 +53,15 @@ namespace BlackMisc
             });
         }
 
+        template<class OBJ, class CONTAINER>
+        OBJ IGeoObjectList<OBJ, CONTAINER>::findFirstWithinRangeOrDefault(const ICoordinateGeodetic &coordinate, const CLength &range) const
+        {
+            return this->container().findFirstByOrDefault([&](const OBJ & geoObj)
+            {
+                return calculateGreatCircleDistance(geoObj, coordinate) <= range;
+            });
+        }
+
         template<class OBJ, class CONTAINER>
         CONTAINER IGeoObjectList<OBJ, CONTAINER>::findWithGeodeticMSLHeight() const
         {
diff --git a/src/blackmisc/geo/geoobjectlist.h b/src/blackmisc/geo/geoobjectlist.h
index cdcc5d392..f44369416 100644
--- a/src/blackmisc/geo/geoobjectlist.h
+++ b/src/blackmisc/geo/geoobjectlist.h
@@ -63,6 +63,9 @@ namespace BlackMisc
             //! \param range      within range of other position
             CONTAINER findWithinRange(const ICoordinateGeodetic &coordinate, const PhysicalQuantities::CLength &range) const;
 
+            //! Find first in range
+            OBJ findFirstWithinRangeOrDefault(const ICoordinateGeodetic &coordinate, const PhysicalQuantities::CLength &range) const;
+
             //! Elements with geodetic height (only MSL)
             CONTAINER findWithGeodeticMSLHeight() const;
 
diff --git a/src/blackmisc/simulation/simulationenvironmentprovider.cpp b/src/blackmisc/simulation/simulationenvironmentprovider.cpp
index 0516bf4d4..fb8f97b5f 100644
--- a/src/blackmisc/simulation/simulationenvironmentprovider.cpp
+++ b/src/blackmisc/simulation/simulationenvironmentprovider.cpp
@@ -91,9 +91,13 @@ namespace BlackMisc
             return delta;
         }
 
-        CElevationPlane ISimulationEnvironmentProvider::findClosestElevationWithinRange(const ICoordinateGeodetic &reference, const PhysicalQuantities::CLength &range) const
+        CElevationPlane ISimulationEnvironmentProvider::findClosestElevationWithinRange(const ICoordinateGeodetic &reference, const CLength &range) const
         {
-            const CCoordinateGeodetic coordinate = this->getElevationCoordinates().findClosestWithinRange(reference, minRange(range));
+            // for single point we use a slightly optimized version
+            const bool singlePoint = (range <= CElevationPlane::singlePointRadius());
+            const CCoordinateGeodetic coordinate = singlePoint ?
+                                                   this->getElevationCoordinates().findFirstWithinRangeOrDefault(reference, CElevationPlane::singlePointRadius()) :
+                                                   this->getElevationCoordinates().findClosestWithinRange(reference, range);
             const bool found = !coordinate.isNull();
             {
                 QWriteLocker l{&m_lockElvCoordinates };