<div dir="ltr"><div>Markus,</div><div>Thank you for working on this! </div><div><br></div><div> Perhaps a flag to default to the transformation with the least error ( via something like the projinfo -s x -t y --summary query and with details captured about the option selected in the metadata)? <a href="https://media.ccc.de/v/bucharest-198-revamp-of-coordinate-reference-system-management-in-the-osgeo-c-c-stack-with-proj-and-gdal#t=666" target="_blank">https://media.ccc.de/v/bucharest-198-revamp-of-coordinate-reference-system-management-in-the-osgeo-c-c-stack-with-proj-and-gdal#t=666</a> around 10:33 minutes in.</div><div><br></div><div>Looking at the reprojection options in QGIS 3.8.2 the menu for picking the reprojection option lists the accuracy, the number of contributing stations, and a preferred alternative. If this data can be gleaned from a projinfo query, a preferred alternative can be established. I would not make that the default.</div><div><br></div><div>A sample workflow would be that someone tries r.proj with no flags. If there are multiple alternatives, it does not proceed and gives a message along the lines of " Multiple projection options detected, please rerun with --info flag to see alternatives.</div><div><br></div><div>User reruns with --info flag ( which supersedes all other flags ) and sees 5 alternatives with accuracy and number of stations listed with an asterisk next to the "preferred" alternative </div><div><br></div><div>User runs r.proj with a --prefer flag that takes the option with the least error and most stations. Alternatively, --file flag that points to a text file with a proj6 pipeline to enforce exactly what is desired.</div><div><br></div><div>The preferred option may not always be the same over time, but if the pipeline is captured in the metadata you will have a record of how it was done.</div><div><br></div><div>Doug</div><div><br></div><div><br></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Tue, Sep 3, 2019 at 10:31 PM Anna Petrášová <<a href="mailto:kratochanna@gmail.com" target="_blank">kratochanna@gmail.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"><div dir="ltr"><div>Hi,</div><div><br></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Tue, Sep 3, 2019 at 4:22 AM Markus Metz <<a href="mailto:markus.metz.giswork@gmail.com" target="_blank">markus.metz.giswork@gmail.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"><div dir="ltr"><div>Hi all,</div><div><br></div><div>there is a new PR for PROJ6 support in GRASS<br><a href="https://github.com/OSGeo/grass/pull/118" target="_blank">https://github.com/OSGeo/grass/pull/118</a><br><br>There are two important changes when using PROJ6:<br><br>First, reprojection with v.proj and r.proj is no longer always possible without the user making informed decisions. The reason is that there can be several different operations available to reproject coordinates from one CRS to another CRS. These different operations are listed and the user has to provide the appropriate operation with the pipeline option, taking care of any axisswap.<br></div></div></blockquote><div><br></div><div>first, thanks for all the work. Second, I don't see how most users are supposed to know what to pick. Is there perhaps a way to pick a good default? I just can't imagine not having r.import/v.import...</div><div><br></div><div>Anna </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr"><div><br>Second, axis order is no longer always easting, northing, e.g. for EPSG:4326 it is northing, easting, and an axisswap might need to be removed from operations provided by PROJ.<br></div><div><br></div><div>There are many more changes (see details in the PR), but these are the two most important ones.<br></div><div><br>Feedback welcome!</div></div>
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</blockquote></div><br clear="all"><div><br></div>-- <br><div dir="ltr" class="m_-3717112289143165689gmail_signature"><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div dir="ltr"><div><div>Doug Newcomb - Cartographer</div><div>USFWS</div><div>551F Pylon Dr</div><div>Raleigh, NC</div><div>919-856-4520 ext. 14 <a href="mailto:doug_newcomb@fws.gov" target="_blank">doug_newcomb@fws.gov</a></div><div>---------------------------------------------------------------------------------------------------------</div><div><br></div></div><div><b style="font-size:12.8px"><i><font color="#0000ff">NOTE: This email correspondence and any attachments to and from this sender is subject to the Freedom of Information Act (FOIA) and may be disclosed to third parties.</font></i></b><span style="color:rgb(0,0,255);font-family:"courier new",monospace;font-size:12.8px"></span><br></div></div></div></div></div></div></div></div></div>