[bugfix] make localization_iterative return dtype be consistent with …

…input dtype

If inputs are arrays, one expects outputs to be arrays. If inputs are
scalars, one expects outputs to be scalars. Many thanks to Pascal Leroux
(IGN) for pointing that out.

rpcm/rpc_model.py

@@ -222,8 +222,8 @@ def localization_iterative(self, col, row, alt, return_normalized=False):
         # use 3 corners of the lon, lat domain and project them into the image
         # to get the first estimation of (lon, lat)
         # EPS is 2 for the first iteration, then 0.1.
-        lon = -np.ones(len(Xf))
-        lat = -np.ones(len(Xf))
+        lon = -ncol ** 0  # vector of ones
+        lat = -ncol ** 0
         EPS = 2
         x0 = apply_rfm(self.col_num, self.col_den, lat, lon, nalt)
         y0 = apply_rfm(self.row_num, self.row_den, lat, lon, nalt)
@@ -250,11 +250,11 @@ def localization_iterative(self, col, row, alt, return_normalized=False):
             # <u, e1> / <e1, e1>
             num = np.sum(np.multiply(u, e1), axis=1)
             den = np.sum(np.multiply(e1, e1), axis=1)
-            a1 = np.divide(num, den)
+            a1 = np.divide(num, den).squeeze()
 
             num = np.sum(np.multiply(u, e2), axis=1)
             den = np.sum(np.multiply(e2, e2), axis=1)
-            a2 = np.divide(num, den)
+            a2 = np.divide(num, den).squeeze()
 
             # use the coefficients a1, a2 to compute an approximation of the
             # point on the gound which in turn will give us the new X0
@@ -279,10 +279,7 @@ def localization_iterative(self, col, row, alt, return_normalized=False):
             lon = lon * self.lon_scale + self.lon_offset
             lat = lat * self.lat_scale + self.lat_offset
 
-        if np.size(lon) == 1 and np.size(lat) == 1:
-            return lon[0], lat[0]
-        else:
-            return lon, lat
+        return lon, lat
 
 
     def incidence_angles(self, lon, lat, z):