In an old map a survey line was drawn with a magnetic bearing of 200° 00′, when the declination was 1° 36′ E. Compute the Magnetic bearing of the line at the time, when the declination is 0° 56′ W.

Q. In an old map a survey line was drawn with a magnetic bearing of 200° 00′, when the declination was 1° 36′ E. Compute the Magnetic bearing of the line at the time, when the declination is 0° 56′ W.

solution :

True bearing of the line= magnetic bearing of th line+ Declination (East)

                                       = 200°00′ +1°36′

                True bearing= 201°36′

The present declination of the line is 0°56′ west

∴ Present Magnetic bearing of the line = True bearing of the line+ Declination (west)

                                     = 201°36’+0°56

   present magnetic bearing  line  = 202°32′