adding distance functions for different coordinate systems

app/sda-workflow/src/shared/neighbourPredicates/DistanceBiPredicate.hpp

@@ -5,18 +5,44 @@
 
 /**
  * @brief Distance BiPredicate Functor.
- * Emits true if the distance between the two shapes is less or equal to the maximum distance.
- * Uses WGS84Ellipsoid distance between the two closest points of the two shapes
+ * Emits true if the distance between the two shapes is less or equal to the maximum distance (in meters).
+ * @tparam DistanceFunction type determining how to calculate the distance between two points in meters.
  */
+template<fishnet::util::BiFunction<fishnet::geometry::Vec2DReal,fishnet::geometry::Vec2DReal, fishnet::math::DEFAULT_FLOATING_POINT> DistanceFunction>
 struct DistanceBiPredicate{
+    DistanceFunction distanceFunction;
     double maxDistanceInMeters;
 
     bool operator()(fishnet::geometry::Shape auto const & lhs, fishnet::geometry::Shape auto const & rhs) const noexcept {
         auto [l,r] = fishnet::geometry::closestPoints(lhs,rhs);
-        return l == r || fishnet::WGS84Ellipsoid::distance(l,r) <= maxDistanceInMeters;
-    }
+        return l == r || distanceFunction(l,r) <= maxDistanceInMeters;
+    }      
 
     static NeighbouringPredicateType type() {
         return NeighbouringPredicateType::DistanceBiPredicate;
     }
-};
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+};
+
+struct WGS84Distance{
+    static auto operator()(const fishnet::geometry::Vec2DReal & lhs, const fishnet::geometry::Vec2DReal & rhs) noexcept {
+        return fishnet::WGS84Ellipsoid::distance(lhs,rhs);
+    }
+};
+
+struct MetricDistance{
+    static auto operator()(const fishnet::geometry::Vec2DReal & lhs, const fishnet::geometry::Vec2DReal & rhs) noexcept {
+        return lhs.distance(rhs);
+    }
+};
+
+using DistanceFunction = std::function<fishnet::math::DEFAULT_FLOATING_POINT(const fishnet::geometry::Vec2DReal &, const fishnet::geometry::Vec2DReal &)>;
+
+static DistanceFunction distanceFunctionForSpatialReference(const OGRSpatialReference & spatialRef) {
+    if(spatialRef.IsEmpty())
+        throw std::runtime_error("No distance function available for empty coordinate system");
+    if(spatialRef.IsLocal() || spatialRef.IsProjected())
+        return MetricDistance();
+    if(spatialRef.IsGeographic())
+        return WGS84Distance();
+    throw std::runtime_error("No distance function found for coordinate system: \""+std::string(spatialRef.GetName())+"\"");
+}
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