Text 14786, 66 rader
Skriven 2008-05-04 12:07:24 av Roy Witt (1:397/22)
  Kommentar till text 14781 av mark lewis (1:3634/12.0)
Ärende: Google Earth
====================
02 May 08 14:49, mark lewis wrote to Roy Witt:


 ml>>> DMS coords: 59ø19'58.04" N 18ø03'52.16" E
 ml>>> DEC coords: 59.332789      18.064489

 ml>>> much much much difference between them ;)

 BF>>> Not if you only look at the value of the figures.

 ml>> hunh?

 RW>> I don't think he grasps the difference and how to get there from
 RW>> here. He takes the DMS number and puts a decimal point after the
 RW>> degrees and then inserts the minutes and seconds after. Which to
 RW>> him converts it to a DEC number.

 ml> you might be right... i'm aware of numerous map coordinate systems
 ml> that are in active use each and every day... for example, all of the
 ml> following represent the exact same spot on the map...

 ml> DMS  : Lat 59ø19'58.04"N  Lon 18ø03'52.16"E
 ml> Dd   : Lat 59.332789N     Lon 18.064489E
 ml> DMd  : Lat 59ø19.9673N    Lon 18ø03.8693E
 ml> UTM  : 34 V 21 6580789.975 Northing  333013.3816Easting
 ml> MGRS : 34 V CL 80789 Northing  33013 Easting
 ml> MhGS : JO99ah  (Jay Oh Nine Nine A Ach {ch as in choose})

 ml> DMS  = Degrees Minutes Seconds
 ml> Dd   = Degrees in decimal
 ml> DMd  = Degrees Minutes in decimal
 ml> UTM  = Universal Transverse Mercator
 ml> MGRS = Military Grid Reference System
 ml> MhGS = Maidenhaed Grid System aka QTH Locator aka WWL (World Wide
 ml> Locator)

 ml> the MhGS/QTH/WWL system is used by HAMs and other radio operators...

I never did like that system.

 ml> it is named for the town outside of London where it was first
 ml> conceived during a 1980 meeting of European VHF operators ;)

 ml> in the MhGS, each grid square is 1øLat by 2øLon (aprox 70mi x
 ml> 100mi)... the first two letters are the "field"... the two numbers
 ml> are the "square"... the final two letters are a finer grid break down
 ml> within the current grid square... this finer grid has each of its
 ml> squares measuring 2.5 min Lat by 5 min Lon which is roughly a 3mi x
 ml> 4mi square...

Of course, you have to have a map of these coordinates to understand it.

 ml> contrast the MhGS with the UTM system which uses grid squares of 1km
 ml> x 1km ;)

I once attempted to write a basic program that used the grid squares of
a Thomas Map Book of San Diego county...to scale, they were/are 1 1/4 mile
squares...of course, the maps had plenty of flaws so it was a useless
endeavor.

                R\%/itt



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