World Magnetic Model

[Olly Betts]

On Thu, Apr 11, 2019 at 11:08:26PM +0100, Olly Betts wrote:
> On Thu, Apr 11, 2019 at 06:03:39PM +0200, Martin Budaj via Therion wrote:
> > On Thu, Apr 11, 2019 at 5:05 PM kevin dixon via Therion <therion at speleo.sk>
> > wrote:
> > > There has in recent years been a significant change of the Magnetic North
> > > Pole location, less so for the Geomagnetic South Pole:
> > > https://ngdc.noaa.gov/geomag/GeomagneticPoles.shtml
> > >
> > > Given the above, an out of cycle World Geomagnetic Model WMM2015v2 was
> > > released 04 Feb 2019.
> 
> Shortly after WMM2015v2 was released I did some comparisons for
> Northerly locations on land between WMM2015v2 and IGRF12 for dates at
> the end of this year (since IGRF13 is due out in December 2019) and the
> largest difference I found was 0.1° which is probably acceptable given
> the accuracy of the readings involved (and considering this is only an
> issue until this December anyway).
> 
> > > When will this update appear in Survex and Therion ?
> 
> My current plan for Survex is to address this by updating to IGRF13 in
> December 2019.

I've now pushed the changes to the Survex git repo to update to IGRF13,
and they'll be in Survex 1.2.43, hopefully fairly soon (ideally I'd like
to fix a bug with SVG export first).

I see Martin B. updated therion's git repo last month, so the next
therion release should also support IGRF13.

Cheers,
    Olly