[Qgis-user] Projections

[Falk Huettmann]

Hi there, Mike et al,

thanks,
but if you check up with Thomas Alerstam  from Sweden - as a bird tracking
migration person you really ought to know those things and his entire
books/papers -
there is sufficient literature on the topic for years re. projections, e.g.
this one for starters.
https://www.researchgate.net/publication/12122402_Migration_Along_Orthodromic_Sun_Compass_Routes_by_Arctic_Birds

Some others are found with the navigation sciences, with sea turtle math
work (former Ram Myers) and then rocket and missile targeting of course.
It's usually not written though by geography or GIS experts. The Google
Earth maps boldly ignore the projection issue (as they are just a shiny
commercial PR tool).

Overall, for birds these days, the public resource question should sit on
CONSERVATION and sustainable management,
not ivory-tower questions. The latter have been done for centuries without
relevant outcome and progress.
Yes, the earth is round and an optimal route exist, but now what ? Birds
know and used that for millennia and their presences show it no other..
Data exist to that degree.
Other problems are more relevant these days.

A nice question why after 100 years of research on bird migration,
state-funded with $Mio's, and with MPI and Movebank, ICARUS etc
no readily available solution or answer exist in R or GIS etc.

That's my opinion and answer on your question. Feel free to follow up as
needed.

Best regards
   Falk Huettmann PhD, Professor
     Uni of Alaska Fairbanks


On Wed, Oct 21, 2020 at 11:53 PM MIKE MCGRADY <mikemcgrady at hotmail.com>
wrote:

> As far as I can recall, few studies of long-distance migratory species
> state what projections are used.  Is there any published study of the
> effect of projections on analyses of animal movement?
>
> M
>
> M. J. McGrady
> Am Rosenhugel 59
> A-3500 Krems
> Austria
>
> ------------------------------
> *From:* Qgis-user <qgis-user-bounces at lists.osgeo.org> on behalf of Hernán
> De Angelis <variablestarlight at gmail.com>
> *Sent:* Thursday, October 22, 2020 6:57 AM
> *To:* qgis-user at lists.osgeo.org <qgis-user at lists.osgeo.org>
> *Subject:* Re: [Qgis-user] Projections
>
>
> Mike
>
>
> For measuring the kind of distances you are mentioning I would suggest
> using ellipsoidal (geodetic) distances rather than projected distances.
> This is because projected distances can become very inaccurate over large
> regions (depending on the particular projection of course).
>
>
> If measuring areas is important consider an equal area projection, like
> Albers for example, not a conformal one like Lambert.
>
>
> Hope this helps.
>
>
> /H.
>
>
>
>
> On 2020-10-22 07:43, MIKE MCGRADY wrote:
>
> I have data on tracked migratory birds, and want accurate measures of
> distance travelled during migration and areas of summering and wintering
> ranges.  These birds are summering in central Asia (mostly Kazakhstan and
> southern Russia), and wintering in Arabia.  Any advice on which projection
> to use?  My guess is Lambert conformal conic.  I'd really like to avoid
> using different projections for different phases of the birds' annual
> cycle, unless absolutely necessary.
>
> M. J. McGrady
> Am Rosenhugel 59
> A-3500 Krems
> Austria
>
> _______________________________________________
> Qgis-user mailing listQgis-user at lists.osgeo.org
> List info: https://lists.osgeo.org/mailman/listinfo/qgis-user
> Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user
>
> _______________________________________________
> Qgis-user mailing list
> Qgis-user at lists.osgeo.org
> List info: https://lists.osgeo.org/mailman/listinfo/qgis-user
> Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.osgeo.org/pipermail/qgis-user/attachments/20201022/3a6bbe1d/attachment.html>