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List: qgis-user
Subject: Re: [Qgis-user] Mac 3.14 dmg, proj
From: John Layt <jlayt () kde ! org>
Date: 2020-07-25 21:21:55
Message-ID: CAM1DM6=vSb3FX-yYu+KQWdQ=fyuWR9LP++qtGRCSjVaeKu-_SA () mail ! gmail ! com
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Hi,
It was being worked on at this GitHub issue
https://github.com/qgis/QGIS-Mac-Packager/issues/12, and thanks to a GIS
grant (http://blog.qgis.org/2020/07/10/qgis-grant-programme-2020-results/)
the first test version are now available. No ETA for final release as yet
but I'd assume 3.16 now.
Cheers!
John.
On Sat, 25 Jul 2020 at 13:46, Greg Troxel <gdt@lexort.com> wrote:
> tl;dr: Why does the mac 3.14 installer use old proj?
>
>
> I've been using 3.10 on NetBSD (built from pkgsrc, against proj 6.3.2),
> and on a mac (downloaded from qgis.org).
>
> I have imagery data in NAD83(2011), claimed to be registered to 0.1m,
> and a point feature in ITRF2014 (also about 0.1m), and I am partly
> trying to check imagery registration, partly just getting used to qgis.
> With the NetBSD build, everything makes sense. With the Mac build, the
> alignment of the two is different (and I think wrong). The Mac build is
> using proj 5.2.0 and probably is using WGS84 as a pivot datum. I bet
> this is using a null transform from NAD83 to WGS84 and then from WGS84
> to ITRF2014, and this is wrong by a meter when transforming modern NAD83
> to ITRF2014. (I understand how this came to be, why it's been replaced
> and why it gets low accuracy answers. Regional ground motion is low
> enough not to matter at the level of accuracy I am achieving so far.)
>
> I then installed 3.14.1 on the Mac, from qgis.org, and still got bad
> registration, and saw that it's still using proj 5.2.0. I had hoped
> that moving off of LTR would get me up-to-date proj.
>
> It seems obvious to me (said knowing that's very dangerous!) that it's
> better to use newer proj with qgis to get the more accurate transforms,
> and that a lot of work has been done in both proj and qgis, so I wonder
> why the 3.14 official mac build is using old proj, and what the plans
> are for moving to proj 6.3.2 or 7.x.
>
> I'm going to try to build qgis on the mac, using pkgsrc, which will use
> newer proj, and see how that is, but I expect to get the same behavior
> (that I think is right/better) because it's building the same sources as
> I built on NetBSD.
>
> Thanks for any insight anyone can provide,
> Greg
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<div dir="ltr"><div>Hi,</div><div><br></div><div>It was being worked on at this GitHub issue <a \
href="https://github.com/qgis/QGIS-Mac-Packager/issues/12">https://github.com/qgis/QGIS-Mac-Packager/issues/12</a>, \
and thanks to a GIS grant (<a \
href="http://blog.qgis.org/2020/07/10/qgis-grant-programme-2020-results/">http://blog.qgis.org/2020/07/10/qgis-grant-programme-2020-results/</a>) \
the first test version are now available. No ETA for final release as yet but I'd assume 3.16 \
now.</div><div><br></div><div>Cheers!</div><div><br></div><div>John.<br></div><div><br></div></div><br><div \
class="gmail_quote"><div dir="ltr" class="gmail_attr">On Sat, 25 Jul 2020 at 13:46, Greg Troxel <<a \
href="mailto:gdt@lexort.com">gdt@lexort.com</a>> wrote:<br></div><blockquote class="gmail_quote" \
style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">tl;dr: Why does \
the mac 3.14 installer use old proj?<br> <br>
<br>
I've been using 3.10 on NetBSD (built from pkgsrc, against proj 6.3.2),<br>
and on a mac (downloaded from <a href="http://qgis.org" rel="noreferrer" \
target="_blank">qgis.org</a>).<br> <br>
I have imagery data in NAD83(2011), claimed to be registered to 0.1m,<br>
and a point feature in ITRF2014 (also about 0.1m), and I am partly<br>
trying to check imagery registration, partly just getting used to qgis.<br>
With the NetBSD build, everything makes sense. With the Mac build, the<br>
alignment of the two is different (and I think wrong). The Mac build is<br>
using proj 5.2.0 and probably is using WGS84 as a pivot datum. I bet<br>
this is using a null transform from NAD83 to WGS84 and then from WGS84<br>
to ITRF2014, and this is wrong by a meter when transforming modern NAD83<br>
to ITRF2014. (I understand how this came to be, why it's been replaced<br>
and why it gets low accuracy answers. Regional ground motion is low<br>
enough not to matter at the level of accuracy I am achieving so far.)<br>
<br>
I then installed 3.14.1 on the Mac, from <a href="http://qgis.org" rel="noreferrer" \
target="_blank">qgis.org</a>, and still got bad<br> registration, and saw that it's still using proj \
5.2.0. I had hoped<br> that moving off of LTR would get me up-to-date proj.<br>
<br>
It seems obvious to me (said knowing that's very dangerous!) that it's<br>
better to use newer proj with qgis to get the more accurate transforms,<br>
and that a lot of work has been done in both proj and qgis, so I wonder<br>
why the 3.14 official mac build is using old proj, and what the plans<br>
are for moving to proj 6.3.2 or 7.x.<br>
<br>
I'm going to try to build qgis on the mac, using pkgsrc, which will use<br>
newer proj, and see how that is, but I expect to get the same behavior<br>
(that I think is right/better) because it's building the same sources as<br>
I built on NetBSD.<br>
<br>
Thanks for any insight anyone can provide,<br>
Greg<br>
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