Hello I saw the discussion of the Georeferencer improvements from April. I hope you don't mind if I revive it and chime in in case these improvements are under consideration. I posted this as a github issue <https://github.com/qgis/QGIS/issues/35051> but maybe it'll get seen here. Great there are plans to work on the UI of Georeferencer. I did a lot of georeferencing work in Arcmap 10.x years ago and have recently been doing quite a bit of work in QGIS3 so I thought based on my experience with both i would type up some of the aspects of QGIS Georeferencer I that think could be modified for easier flow. Some of these are pretty basic (more basic than what is proposed above) but still fall under the Feature Request category.
1. Allow rotating the original 90 deg in the Preview window (arcmap allows this). I have to flip original and GCPs around in my mind every time i move my eyes between the windows.I saw discussion of a preview mode in Georeferencer in the main window and I think this would be a great. At the very least allowing 90deg rotation would allow us to get the original closer to the realworld orientation.I've tried rotating the originals in image editor and this sometimes works. Better to support rotating inside Georeferencer if possible. <http://osgeo-org.1560.x6.nabble.com/file/t387047/94373373-f4be6400-00b9-11eb-9d72-f19176dd442a.jpg> 2. Auto-Filenaming of GCP.points file: In Georeferencer > Transform Settings dialog the "Save GCP points" checkbox currently results in a GCP file called output_filename.tif.points. However because the .points GCP file works with the original scan file not the output_filename.tif. perhaps it is more intuitive to have the checkbox "Save GCP points" auto-create a points file called input_filename.tif.points. I guess the one good thing to the current approach is the output points are linked to the step in georeferencing by the filename. But the problem is one assumes they should be loaded along with that file when in fact they were used to produce it. 3. File> Reset Georeferencer removes all the GCP points and the raster as well. If I reload the raster the GCPs come back. How do i just remove all the GCPs and start fresh with the same raster? (this may be a bug) 4. As the original post suggests this work is occurring in the main map window (good for smaller screens) and not in a separate window. A separate window is optionally available in Arcmap. 5. In Arcmap the GCP number is visible (consistently colored green and thin font no label buffer like in Q), while the target GCP crosshair and label are consistently red color. snapping result hover label showing what layer it is snapping to GCP Link table (docked) shows residual with X and Y separate as well as transform type <http://osgeo-org.1560.x6.nabble.com/file/t387047/94373677-c772b580-00bb-11eb-9bd6-26384319b900.jpg> 6. What about Z values? In steep terrain the lack of Z will introduce great distortions. 7. In Arcmap the georeferencer is doing realtime collinearity and distribution tests whenever a new GCP is placed (as soon as 3 or more GCPs have been placed). This warning pops up if all the GCPs are clustered or along one edge <http://osgeo-org.1560.x6.nabble.com/file/t387047/94373848-fc333c80-00bc-11eb-9089-fca124a9da83.jpg> The result is that Arcmap allows an iterative process. First place 4 GCPs roughly around the perimeter to get the thing preview-positioned in the main map window. Keep working carefully placing GCPs # 4-8 or more, then investigate residuals and remove / relocate the GCPs with a high residual. Related to this I recently typed up a QGIS Georeferencer + JOSM workflow on the OSM wiki to help historical mappers to geolocate the excellent Sanborn maps for OHM contributions. Thanks Sanborn_Map_geoferencing for OpenHistoricalMap.org <https://wiki.openstreetmap.org/wiki/Sanborn_Map_geoferencing> Thank you for this excellent Georef tool in QGIS so far. I've found that the QGIS Georeferencer produces often cleaner GeoTIFF files than Arcmap -- kudos team! -- Sent from: http://osgeo-org.1560.x6.nabble.com/QGIS-Developer-f4099106.html _______________________________________________ QGIS-Developer mailing list [email protected] List info: https://lists.osgeo.org/mailman/listinfo/qgis-developer Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-developer
