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Formulae:
1) Altitude factor= R/(R+Altitude)
R= average earth curvature radius
Altitude: The altitude above average sea level
2) Scale factor= The scale factor on the station
3) Grid scale factor = Altitude factor×Scale factor
Distance measuring:
1)Grid scale distance(HDg)= HD×Grid scale factor
HD= distance on the ground
2) Distance on the ground(HD)= HDg/Grid scale factor
Enter altitude in the „Altitude‟ column and press soft key
„Enter‟ to calculate the Grid scale factor as shown in the picture
above. Press „ENT‟ to save the Grid scale and end the dialogue
box. A box saying „Saved‟ will flash once.
Grid scale calculated being less than 0.99 or greater than
1.01 indicates that there must be an error or errors in entering
altitude or scale or both. The calculated Grid scale cannot be
accepted by the system and users must re-enter the factors. Quit
with key „ESC‟, the new Grid scale will not be saved.
Gird scale
=0.999984
Altitude:
100
1.000000
B.S
Clear
Ente
r