Update README.md

README.md

@@ -19,10 +19,22 @@
         make install
     just wait and you can get libs and includes in install dir
 ```
-3. install ros2
+3. install ros-melodic and cartographer_ros
 ```
-    (1) As "1." first step shows,get ros2 pkg according to your platform.
-    (2) 
+    if you want to try ros2,please follow the step-1. but cartographer support no well for ros2, so ros1 recommended.
+    (1) follow these steps by link:http://wiki.ros.org/cn/melodic/Installation/Ubuntu, if sudo rosdep init failed beacause of network,try "sudo vim /etc/hosts" and add "151.101.84.133 raw.githubusercontent.com" at the last line. Then cd main dir and "mkdir -p cartographer_ws/src" and cd to cartographer_ws/src and "catkin_init_workspace"
+    (2) "unzip cartographer_ros.zip" and copy to cartographer_ws/src that created before. please modify the CMakeLists.txt before the line with find_package(cartographer REQUIRED) as your own cartographer.so install_dir in all pkgs
+        "cd cartographer_ws"
+        "catkin_make -j2"
+        "source /opt/ros/melodic/setup.bash"
+        "source devel/setup.bash"
+    Attention: configuration_files ".lua" have been copied to cartographer_ws. so just test it.
 ```
+4. test cartographer_ros
+    (1) download bag datasets or record your own data
+        wget -P ~/Downloads https://storage.googleapis.com/cartographer-public-data/bags/backpack_2d/b2-2016-04-05-14-44-52.bag
+        wget -P ~/Downloads https://storage.googleapis.com/cartographer-public-data/bags/backpack_2d/b2-2016-04-27-12-31-41.bag
+    (2) run demo
+        roslaunch cartographer_ros demo_backpack_2d.launch bag_filename:=${BAG_DIR}/cartographer_paper_deutsches_museum.bag
 
-
+5. Have a wonderful learning trip. Thanks