Global Mapper v25.0

What are "Grades (French Angular Units)"?

macwind
macwind Global Mapper User
edited October 2011 in Technical Support
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.

Comments

  • macwind
    macwind Global Mapper User
    edited June 2011
    In my opinion, the "GRADES (FRENCH ANGULAR UNITS)" (-3.2141115177,48.0810881343) are wrong if you consider:
    degrees + 1/60*minutes + 1/3600*seconds
  • global_mapper
    global_mapper Administrator
    edited June 2011
    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
  • KGJames
    KGJames Global Mapper User Trusted User
    edited October 2011
    Grads were once much used by the artillery. To avoid the use of decimals for high precision, they also used "mils" (milligrads).