What are "Grades (French Angular Units)"?
macwind
Global Mapper User
Hi.
A friend of mine (Amaiuki) is wondering about the meaning of "Grades (French Angular Units)" when you select the units in a Geographic Projection. How does GlobalMapper calculate it?
This is the point in "ARC DEGREES":
2° 53' 33.7213" W,43° 16' 22.7256" N
This is the point in "GRADES (FRENCH ANGULAR UNITS)":
-3.2141115177,48.0810881343
How is this calculated? Is there any option to obtain:
2.892700361,43.27297933
(the coordinates in grades with decimals)?
The version of GlobalMapper my friend uses is v11.02. Thank you very much in advance.
A friend of mine (Amaiuki) is wondering about the meaning of "Grades (French Angular Units)" when you select the units in a Geographic Projection. How does GlobalMapper calculate it?
This is the point in "ARC DEGREES":
2° 53' 33.7213" W,43° 16' 22.7256" N
This is the point in "GRADES (FRENCH ANGULAR UNITS)":
-3.2141115177,48.0810881343
How is this calculated? Is there any option to obtain:
2.892700361,43.27297933
(the coordinates in grades with decimals)?
The version of GlobalMapper my friend uses is v11.02. Thank you very much in advance.
Comments
-
In my opinion, the "GRADES (FRENCH ANGULAR UNITS)" (-3.2141115177,48.0810881343) are wrong if you consider:
degrees + 1/60*minutes + 1/3600*seconds -
A degree is equal to 0.9 grades. So the decimal degree of 2° 53' 33.7213" is 2.892700361. Dividing that by 0.9 gives you 3.2141115 which matches what Global Mapper is reporting.
Let me know if I can be of further assistance.
Thanks,
Mike
Global Mapper Support
support@globalmapper.com -
Grads were once much used by the artillery. To avoid the use of decimals for high precision, they also used "mils" (milligrads).
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