1.errror:[ERROR] [1388762076.282169241]: Skipping XML Document "/opt/ros/indigo/share/gmapping/nodelet_plugins.xml" which had no Root Element. This likely means the XML is malformed or missing.

解決："/opt/ros/indigo/share/gmapping/nodelet_plugins.xml" which had no Root Element.

以前包的bug現在新版本已經修復了，該提示一般不會影響其他節點使用。如果需要修復，可以找到相對應xml檔案，複製到該目錄即可。

這裡給出一份xml檔案：
nodelet_plugins.xml

cd /opt/ros/indigo/share/gmapping
sudo gedit nodelet_plugins.xml

<library path="lib/libslam_gmapping_nodelet">
  <class name="SlamGMappingNodelet" type="SlamGMappingNodelet" base_class_type="nodelet::Nodelet">
  <description>
  Nodelet ROS wrapper for OpenSlam's Gmapping.
  </
 
description>
  </class>
</library>

改完之後，又出現以下錯誤…

2. You must specify at least three points for the robot footprint,reverting to previous footprint

解決：[問題]You must specify at least three points for the robot footprint,reverting to previous footprint 的解決辦法

roscd turtlebot_navigation
cd param
sudo gedit costmap_common_params.yaml
 

做如下更改

#robot_radius: 0.20  # distance a circular robot should be clear of the obstacle (kobuki: 0.18)
footprint: [[0.1, 0.1], [-0.1, 0.1], [-0.1, -0.1], [0.1, -0.1] ]  # if the robot is not circular

[更改日期]：2018-10-28,下午三點半