diff --git a/cartographer/io/pcd_writing_points_processor.cc b/cartographer/io/pcd_writing_points_processor.cc
index 9a52762163..a871b6e1b8 100644
--- a/cartographer/io/pcd_writing_points_processor.cc
+++ b/cartographer/io/pcd_writing_points_processor.cc
@@ -34,15 +34,15 @@ namespace {
 // 'output_file'.
 void WriteBinaryPcdHeader(const bool has_color, const bool has_intensities,
                           const int64 num_points, FileWriter* const file_writer) {
-  std::string color_header_field = !has_color ? "" : " rgb";
-  std::string color_header_type = !has_color ? "" : " U";
-  std::string color_header_size = !has_color ? "" : " 4";
-  std::string color_header_count = !has_color ? "" : " 1";
+  const std::string color_header_field = !has_color ? "" : " rgb";
+  const std::string color_header_type = !has_color ? "" : " U";
+  const std::string color_header_size = !has_color ? "" : " 4";
+  const std::string color_header_count = !has_color ? "" : " 1";
 
-  std::string intensity_header_field = !has_intensities ? "" : " intensity";
-  std::string intensity_header_type = !has_intensities ? "" : " F";
-  std::string intensity_header_size = !has_intensities ? "" : " 4";
-  std::string intensity_header_count = !has_intensities ? "" : " 1";
+  const std::string intensity_header_field = !has_intensities ? "" : " intensity";
+  const std::string intensity_header_type = !has_intensities ? "" : " F";
+  const std::string intensity_header_size = !has_intensities ? "" : " 4";
+  const std::string intensity_header_count = !has_intensities ? "" : " 1";
 
   std::ostringstream stream;
   stream << "# generated by Cartographer\n"
@@ -71,9 +71,10 @@ void WriteBinaryPcdPointCoordinate(const Eigen::Vector3f& point,
 }
 
 void WriteBinaryPcdIntensity(const float intensity,
-                             FileWriter* const file_writer) {
-  CHECK(file_writer->Write(reinterpret_cast<const char*>(&intensity),
-                           sizeof(float)));
+                                 FileWriter* const file_writer) {
+  char buffer[4];
+  memcpy(buffer, &intensity, sizeof(float));
+  CHECK(file_writer->Write(buffer, 4));
 }
 
 void WriteBinaryPcdPointColor(const Uint8Color& color,