It is a feature that creates maps from geographic data. Whoitam Image Measurement can connect to data to draw maps. Another means of connecting to data is simply a file. NMEA data is in text form and can be logged using GPS device or any other terminal program capable of storing RS-232 data to a file. Whoitam Image Measurement can read through a NMEA file and use the data to draw map just as it would connected through a RS-232 communications port. Using the NMEA data from the GPS receiver, Whoitam Image Measurement will display various statuses graphically. First set resolution of whole cad like 5 square kilometer or 100 square kilometer etc. Then you will see the recommended calibration for measuring. Select a point on cad where first tracking will start. Then set scale and click on “Start Drawing”.