how to convert point cloud to map

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hey i m new to ros and currently working on building my own mapping algorithm i converted laserscan value to point cloud by using the range values as : x-coordinate = range *cos (angle) y-coordinate = range *sin (angle) current angle or orientation = tan(y-coordinate/x-coordinate) am i doing it right ?
if yes how to print it in rviz as in pointcloudmsgs and also how to use scan matching further