This is not relevant to the original question but since Jeff mentioned QGISs quirky coordinate system menu I'll add that I absolutely hate the way it organizers coordinate systems! Organizing by projection type rather than region/coverage extent is absurd in my opinion. But I do love how it gives a live thumbnail of the coverage. Also adding a link to my Cartographic Design Resources page below. It has a small section on coordinate systems that may have some useful links in it. The "I hate Coordinate Systems!" one is particularly useful ; ) https://sites.google.com/stanford.edu/gis-cartography/link-list [https://lh3.googleusercontent.com/sd_rvwBoYbtDorfaArv3mt2ML605dUq9OIwPYcaIzSBZAw7bjty-cpN4GKC7HTniymqFOw=w16383]<https://sites.google.com/stanford.edu/gis-cartography/link-list> GIS Cartography - Google Sites: Sign-in<https://sites.google.com/stanford.edu/gis-cartography/link-list> Stanford Geospatial Center Reading General Texts Making Maps: A Visual Guide to Map Design for GIS - Krygier, Wood (@Stanford) Cartography: An Introduction, 2nd - BCS (@Stanford) Cartography Guide - Axis Maps Advanced Texts Cartography - Ken Fields (@Stanford) Cartographic Relief Presentation - sites.google.com David David Medeiros Geospatial Reference & Instruction Specialist Stanford Geospatial Center 650.561.5294 @mapbliss SGC website: gis.stanford.edu GIS cartography: bit.ly/giscart<http://bit.ly/giscart><http://bit.ly/giscart> GIS email list: bit.ly/GISlist ________________________________ From: Maps-L: Map Librarians, etc. <[log in to unmask]> on behalf of Jeff Essic <[log in to unmask]> Sent: Friday, May 20, 2022 8:13 AM To: [log in to unmask] <[log in to unmask]> Subject: Re: QGIS, question about projection transformation screen Tony, This is a great question, and I really appreciate the responses you've received so far. To your initial question of "what transformation would one use and why?" and looking at your screenshot, in my opinion, I would advise the students to not use the first option which results in accuracy to 4 meters, but instead to use one of choices below it with accuracy to 2 meters. You should look at the additional descriptions to pick the best one of the remaining 6. I have seen QGIS put the least accurate choice at the top before, and often people will just choose the top (default) option, so I think this is problematic. QGIS handles coordinate systems, projections, re-projections, etc. quite differently than ArcGIS, and for the most part, I prefer QGIS overall. One thing that bothers me though is when you open the CRS window, all the Predefined CRS options are expanded out by default, and it takes forever to scroll through that list. If they were not expanded, it would be much simpler to me. Really the Filter is the only way to find what you need, but I would prefer to drill-down like with ArcGIS. Thanks again, Jeff Essic GIS and Data Librarian North Carolina State University D.H. Hill, Jr. Library; Data & Visualization Services Box 7111, Raleigh, NC 27695-7111 (919) 515-5698 http://www.lib.ncsu.edu/gis On Thu, May 19, 2022 at 10:33 AM Diaz, Tony A. <[log in to unmask]<mailto:[log in to unmask]>> wrote: Hi folks, I’m going to start teaching an introduction to QGIS class later this year, for newly arriving students here at my institute. Would anyone have an easy explanation I can say about projection transformations? I have an idea of what it is, but I was hoping if someone could chime in on a simple explanation for someone new to GIS to understand what this means when a user comes across it. Also, what transformation would one use and why? (Example, in the attached screenshot, which of these would I choose and why). Thanks again, Tony Diaz California Institute of Technology Pasadena, CA