My shapefile inexplicably malfunctioned!

Good afternoon,

I am currently working on my own continental polygon shapefile (.shp) in QGIS. Using the CEED shapefile as a base, I have been redrawing the polygons and their boundaries using the Split Features, Merge Selected Features, and Reshape Features tools to add more detail. This worked well for a while; the shapefile was perfectly readable by both GPlates and QGIS, and edits made using the latter software showed up well in the former.

But when I then tried to edit the shapefile in GPlates to rename some of the cookie-cut polygons and change their appearance times, I got an error message when I attempted to save the file. I tried to “Save As” in .shp format and the same message popped up. So I then saved the shapefile as a .gpml and this worked…

Except that when I attempt to save this .gpml as a shapefile again, it fails and I get an error message. Meanwhile, the original .shp file that was edited in QGIS no longer works at all. GPlates gives me a Failure to Begin. QGIS cannot begin to load it either, and when I opened a project file that used that shapefile as a layer source, I got a message stating that that layer was missing a source.

I don’t know what I did wrong here, but I think I messed up in a big, serious way. I have attached a link to a zip file that contains the original corrupted shapefile, the functional .gpml file produced from it that cannot be converted back to .shp, and some other files that accompany the shapefile. I hope that by carefully examining these files, the cause(s) of the aforementioned sticky situation can be identified and a solution found.

ZIP archive containing problematic files


by the sounds of it you were just asking for serious trouble by editing a single file concurrently in GPlates and QGIS (this is not just limited to those two applications but will happen in many, actually).

What works is editing a file in QGIS and reading in GPlates (clicking the Reload button in the Manage features window - CTRL+m shortcut). Having the file in edit mode in QGIS and modifying features in GPlates at the same time will cause failure as both applications try to modify the file at the same time. As QGIS locks the file, GPlates complains and throws an error. I’m sure @john.cannon can explain the mechanics of it much better.

What sometimes works to save the file from being completely unreadable is to reload the file in GPlates (which of course makes you loose those edits).

Anyway, long story short: Don’t edit the file in two applications at the same time.