Falling hard with an appropriate error message would be good: it’s obvious then that the available data is invalid, and why. And the message should include the hint to the declination command to fix this.
> Am 05.10.2020 um 20:40 schrieb Bruce Mutton <[email protected]>: > > > Hi Matt > I think these issues have been raised previously. > The error message for dates later than those included in the Therion model > was inaccurate, as you point out. I ‘think’ that in recent versions this may > have been replaced with a more meaningful message. > > And then the question of whether it is better for Therion to extrapolate > future declinations, or set them to zero? > Shades of failing gracefully or abruptly, I guess. I could take either side, > but I think my preference would be for Therion to set declinations beyond > those modelled to zero. This way it is more likely that users will detect > the problem (as you have), and either upgrade to a more recent version of > Therion, or manually set the declination for each affected survey, using the > declination statement. > > Bruce > > From: Therion <[email protected]> On Behalf Of Matthias Keller > Sent: Monday, 5 October 2020 21:40 > To: [email protected] > Subject: [Therion] Therion uses wrong declination for surveys 'in the future' > > Hi > > I just had the following problem: A current survey (with survey dates > 2020.06.27 and 2020.09.19) was compiled using Therion 5.4.4 (from 2019). I > got the following warning during compilation: > > warning -- unable to determine magnetic declination for undated surveys > > However, firstly: this warning is wrong, as all surveys are dated correctly. > > However I was stunned by some large loop errors in the newest surveys (>60cm > in only 10 legs). Then, just by some other impulse I updated therion to 5.5.1 > and suddenly, those errors went down to <10cm and the generated models looked > differently. Also, the above error message was not present anymore. > > So i experimented and just added "declination 3 deg" to the two new surveys > (from June and September) and suddenly, the output generated by 5.4.4 looked > pretty much as the one from 5.5.1 > > It appears that, when therion cannot determine the magnetic declination of a > survey (with valid date!), it finally just assumes 0. The problem seems to > be, that the declination data stored in 5.4.4 didn't let therion determine a > possible declination for 2020.06.27 and 2020.09.19 so it just assumed 0. I > would have expected therion to at least consider the latest known declination > which would result to around 3° (in Switzerland). > > Is this a known issue? It just means that whenever you open a survey in some > version being 'too old', it will kill your plans... > > BTW, Therion 5.4.4 seems to have *some* data for 2020 at least, as it seems: > > geomag declinations (deg): > 2019.1.1 2.9201 > 2020.1.1 3.0503 > > but the only surveys from 2020 are the ones from June 2020 and September > 2020, and both were assigned a declination of 0° instead of about 3°. I can > verify that by adding the declination parameter with "0 deg" to those surveys > and the output is identical to the one without this parameter. > > Thanks > > Matt > > _______________________________________________ > Therion mailing list > [email protected] > https://mailman.speleo.sk/listinfo/therion
_______________________________________________ Therion mailing list [email protected] https://mailman.speleo.sk/listinfo/therion
