upd throw msgs

Sample/Interface/RoughnessMap.cpp

@@ -58,9 +58,9 @@ RoughnessMap::RoughnessMap(size_t x_points, size_t y_points, double Lx, double L
     if (y_points == 0)
         throw std::runtime_error("Number of points along Y must be >=1");
     if (Lx <= 0)
-        throw std::runtime_error("X length must be > 0");
+        throw std::runtime_error("Sample X length must be > 0");
     if (Ly <= 0)
-        throw std::runtime_error("Y length must be > 0");
+        throw std::runtime_error("Sample Y length must be > 0");
 }
 
 RoughnessMap::double2d_t RoughnessMap::generateMap()