The last Therion release 5.4.3 is dated 01 Feb 2019. 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. When will this update appear in Survex and Therion ? Thanks, Kevin Dixon
Hi, Therion does not use WMM at all (as it doesn't contain 20th century historical data). It uses IGRF model (https://www.ngdc.noaa.gov/IAGA/vmod/igrf.html) which hasn't been updated yet. Best regards Martin On Thu, Apr 11, 2019 at 5:05 PM kevin dixon via Therion <therion@speleo.sk> wrote:
The last Therion release 5.4.3 is dated 01 Feb 2019.
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.
When will this update appear in Survex and Therion ?
Thanks,
Kevin Dixon _______________________________________________ Therion mailing list Therion@speleo.sk https://mailman.speleo.sk/listinfo/therion
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@speleo.sk> wrote:
The last Therion release 5.4.3 is dated 01 Feb 2019.
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.
Therion does not use WMM at all (as it doesn't contain 20th century historical data). It uses IGRF model (https://www.ngdc.noaa.gov/IAGA/vmod/igrf.html) which hasn't been updated yet.
Survex uses IGRF too, and for the same reason. It'd be nice to support WMM2015v2 but we would still need to use IGRF for dates before 2015 and have some way to cleanly transition between the two (just using IGRF for < 2015 and WMM for >= 2015 would mean that a series of surveys made from late 2014 to early 2015 could have a sudden step in the declination corrections, which seems problematic). I can't speak for Therion, but I'm open to supporting WMM in Survex if the difference is actually an issue for people. But if someone wants WMM support in Survex we at least need a workable plan for what to do about dates that WMM doesn't handle. And even better would be a patch to implement that plan. Cheers, Olly
Hello, For our group, support of old dates (from 1975) is more important than the 0.1° difference in accuracy. Cheers, Michael. www.arge-hoehle-stuttgart.de
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@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
participants (4)
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kevin dixon -
Martin Budaj -
Michael -
Olly Betts