There are many options for measuring perimeter and area:
-The GPS function when you move the map will be calculated continuously according to your location (need to turn on location and allow the app to access the location)
-Or you can mark with the OK GPS button, the app will save that location, to another point you continue to press OK GPS the app will save the next point, and so on will calculate the exact measurement
-The function of hand drawing on the map, can be used to refer to a map area to estimate the area of that area in advance