Angular Deviation

I wrote a piece some time ago about the magnetic deviation between magnetic south and true south in the Macarthur Region of NSW. 

I had two solutions using two methods. One method used a software programme called 'Wingrid' which gave a deviation of 11.2 degrees East. The second method was to use an I-pad app called "Declination" which offered a solution of 12.38 degrees East.

Wingrid is old software, no longer openable on my PCs, so I cannot re-check it.

However, I came across an online calculator at > this location <  provided by the National Oceanic and Atmospheric Administration of the US Government Dept of Commerce. 

This calculated the deviation in my region as follows: 

Two almost identical answers from the same site, providing a magnetic deviation in the Macarthur region of 12.5 degrees East, which coincides almost precisely with the 12.49 degrees currently indicated by the 'Declination' app.

I did also try an app called 'Distance', which gave me a heading of 16.4 degrees, which is clearly innacurate, so maybe I'll leave the headings/bearings calculators to the radio enthusiasts.

The above site can of course be used to determine magnetic deviation at any location on Earth.