Hi to all in Reef master community,
My question is that may I import the text file of water depth and coordinates in the RM2 directly to make water depth map.

Yes, it is possible.

I import csv-files that look like this:

53.843018 , 13.358830 , 2.65, 30.65, 7.01, 21421
53.843018 , 13.358839 , 2.71, 31.43, 7.01, 23435
53.843018 , 13.358848 , 2.67, 32.15, 7.01, 25453
53.843018 , 13.358858 , 2.69, 30.68, 7.01, 27378

lat, lon, depth, hardness value (the last two colums - not sure, temp and something else). Only first three is needed I think.