Don't allow invalid lat/lon in KDTree

The user will get an exception if an invalid lat/lon or x/y coordinate
is provided in Grid, Points, or KDTree. Latitudes must be between [-90
and 90]. Additionally, NaN values are not allowed.

include/gridpp.h

@@ -1236,6 +1236,10 @@ namespace gridpp {
                 private:
                     point p;
             };
+            // Checks that a lat-coordinate is valid (based on the coordinate type)
+            bool check_lat(float lat) const;
+            // Checks that a lon-coordinate is valid (based on the coordinate type)
+            bool check_lon(float lon) const;
     };
 
     /** Represents a vector of locations and their metadata */

src/api/kdtree.cpp

@@ -1,4 +1,5 @@
 #include "gridpp.h"
+#include <iostream>
 
 using namespace gridpp;
 
@@ -117,6 +118,11 @@ bool gridpp::KDTree::convert_coordinates(const vec& lats, const vec& lons, vec&
 }
 
 bool gridpp::KDTree::convert_coordinates(float lat, float lon, float& x_coord, float& y_coord, float& z_coord) const {
+    if(!check_lat(lat) || !check_lon(lon)) {
+        std::stringstream ss;
+        ss << "Invalid coords: " << lat << "," << lon << std::endl;
+        throw std::invalid_argument(ss.str());
+    }
     if(mType == gridpp::Cartesian) {
         x_coord = lon;
         y_coord = lat;
@@ -246,3 +252,12 @@ bool gridpp::KDTree::is_not_equal::operator()(value const& v) const {
     float z0 = v.first.get<2>();
     return p.get<0>() != x0 || p.get<1>() != y0 || p.get<2>() != z0;
 }
+
+bool gridpp::KDTree::check_lat(float lat) const {
+    if(get_coordinate_type() == gridpp::Cartesian)
+        return gridpp::is_valid(lat);
+    return gridpp::is_valid(lat) && (lat >= -90.001) && (lat <= 90.001);
+};
+bool gridpp::KDTree::check_lon(float lon) const {
+    return gridpp::is_valid(lon);
+}

tests/kdtree_test.py

@@ -89,6 +89,44 @@ def test_empty_constructor(self):
         tree = gridpp.KDTree()
         self.assertEqual(tree.get_coordinate_type(), gridpp.Geodetic)
 
+    def test_invalid_coords(self):
+        lats = [91, -91, np.nan, 0]
+        lons = [0, 0, 0, np.nan]
+        for i in range(len(lats)):
+            curr_lats = [lats[i]]
+            curr_lons = [lons[i]]
+            with self.subTest(lat=lats[i], lon=lons[i]):
+                with self.assertRaises(ValueError) as e:
+                    tree = gridpp.KDTree(curr_lats, curr_lons, gridpp.Geodetic)
+
+    def test_valid_coords(self):
+        lats = [90.000001, -90.0000001]
+        lons = [0, 0]
+        for i in range(len(lats)):
+            curr_lats = [0, lats[i]]
+            curr_lons = [0, lons[i]]
+            with self.subTest(lat=lats[i], lon=lons[i]):
+                tree = gridpp.KDTree(curr_lats, curr_lons, gridpp.Geodetic)
+                I = tree.get_nearest_neighbour(0, 0)
+                self.assertEqual(I, 0)
+
+    def test_wrap_lon(self):
+        """Check that longitudes outside [-180, 180] are correctly handled"""
+        lons = [-360, 0, 360]
+        for i in range(len(lons)):
+            curr_lats = [0]
+            curr_lons = [lons[i]]
+            with self.subTest(lon=lons[i]):
+                tree = gridpp.KDTree(curr_lats, curr_lons, gridpp.Geodetic)
+                I, dist = tree.get_neighbours_with_distance(0, 0, 1e9)
+                self.assertEqual(I[0], 0)
+                self.assertAlmostEqual(dist[0], 0)
+
+                I, dist = tree.get_neighbours_with_distance(0, 180, 1e9)
+                self.assertEqual(I[0], 0)
+                diameter_of_earth = 12756274.0
+                self.assertAlmostEqual(dist[0], diameter_of_earth)
+
 
 if __name__ == '__main__':
     unittest.main()