[DOC] add README.md content for rqt-cristal-map-view

README.md

 # RQT Cristal Map View
 
-# COMING LATER
+## Dependencies 
\ No newline at end of file
+
+This package was validated on ROS Noetic under Ubuntu 20.04. Please install a valid ROS Noetic environment http://wiki.ros.org/noetic/Installation/Ubuntu
+
+It depends on the Qt Location features and QML
+
+```
+sudo apt install qml-module-qtlocation qml-module-qtquick* qml-module-qtpositioning 
+```
+
+## Building 
+
+
+In the workspace folder, use catkin_make to build the package.
+
+## Running 
+
+Clone the repository in the src folder of your ROS workspace: 
+
+```
+cd catkin_ws/src
+git clone https://gitlab.cristal.univ-lille.fr/open-pretil/rqt-cristal-map-view
+```
+
+In the workspace folder : 
+``` 
+source devel/setup.bash
+rqt
+```
+
+In the rqt window, select the menu Plugins -> rqt plugins -> GPS Map View 
+
+Click on the refresh icon to make the data sources available.