diff --git a/GeoLib/Grid.h b/GeoLib/Grid.h
index 548d71554fdfcb114e08e944549fb01c1041abfa..faadd8a360242bc1379f4dd96e819f8b68d1de13 100644
--- a/GeoLib/Grid.h
+++ b/GeoLib/Grid.h
@@ -98,20 +98,20 @@ public:
 						// 2d case
 						if (fabs(delta[1]) < std::numeric_limits<double>::epsilon()) {
 							// y = const
-							_n_steps[0] = static_cast<size_t> (ceil(sqrt(n_pnts * delta[0] / (max_num_per_grid_cell * delta[2]))));
+							_n_steps[0] = static_cast<std::size_t> (ceil(sqrt(n_pnts * delta[0] / (max_num_per_grid_cell * delta[2]))));
 							_n_steps[1] = 1;
 							_n_steps[2] = static_cast<std::size_t> (ceil(_n_steps[0] * delta[2] / delta[0]));
 						} else {
 							if (fabs(delta[2]) < std::numeric_limits<double>::epsilon()) {
 								// z = const
-								_n_steps[0] = static_cast<size_t> (ceil(sqrt(n_pnts * delta[0] / (max_num_per_grid_cell * delta[1]))));
-								_n_steps[1] = static_cast<size_t> (ceil(_n_steps[0] * delta[1] / delta[0]));
+								_n_steps[0] = static_cast<std::size_t> (ceil(sqrt(n_pnts * delta[0] / (max_num_per_grid_cell * delta[1]))));
+								_n_steps[1] = static_cast<std::size_t> (ceil(_n_steps[0] * delta[1] / delta[0]));
 								_n_steps[2] = 1;
 							} else {
 								// x = const
 								_n_steps[0] = 1;
-								_n_steps[1] = static_cast<size_t> (ceil(n_pnts * delta[1] / (max_num_per_grid_cell * delta[2])));
-								_n_steps[2] = static_cast<size_t> (ceil(_n_steps[1] * delta[2] / delta[1]));
+								_n_steps[1] = static_cast<std::size_t> (ceil(n_pnts * delta[1] / (max_num_per_grid_cell * delta[2])));
+								_n_steps[2] = static_cast<std::size_t> (ceil(_n_steps[1] * delta[2] / delta[1]));
 							}
 						}
 					}
@@ -121,8 +121,8 @@ public:
 			// 3d case
 			_n_steps[0] = static_cast<std::size_t> (ceil(pow(n_pnts * delta[0] * delta[0]
 									/ (max_num_per_grid_cell * delta[1] * delta[2]), 1. / 3.)));
-			_n_steps[1] = std::max(static_cast<size_t>(1), std::min(static_cast<size_t> (ceil(_n_steps[0] * delta[1] / delta[0])), static_cast<size_t>(100)));
-			_n_steps[2] = std::max(static_cast<size_t>(1), std::min(static_cast<size_t> (ceil(_n_steps[0] * delta[2] / delta[0])), static_cast<size_t>(100)));
+			_n_steps[1] = std::max(static_cast<std::size_t>(1), std::min(static_cast<std::size_t> (ceil(_n_steps[0] * delta[1] / delta[0])), static_cast<std::size_t>(100)));
+			_n_steps[2] = std::max(static_cast<std::size_t>(1), std::min(static_cast<std::size_t> (ceil(_n_steps[0] * delta[2] / delta[0])), static_cast<std::size_t>(100)));
 		}
 
 		const std::size_t n_plane(_n_steps[0] * _n_steps[1]);