How to Validate & Fix Geometry in QGIS

Video #139
In this 6 minute video, I demonstrate how to validate and fix some polygon geometry when a Clip tool fails to execute.
There are quite a few tools available to help with such problems but this video will show you two key features of QGIS.
QGIS toolbox can of course be used to clean up data destined for MapInfo and ArcGIS if needed.

[@toonverberg1313]

Thanks for sharing your method. Excellent work!

[@zeko-power]

SO simple and helpful thank you so much

[@tb_diary5611]

this was very informative session.

[@danielerinaldi3123]

100 / 5.000 thank you so much, this helpful video🏅 just solved a topological problem🙄 I was struggling with

[@kahimbicharlotte7104]

Thank you this helped😊

[@TheDuke1231]

Very helpful video! Glad I'm not the only one who spends a bit of time fixing geometry (other people's 😆). Couple of things to add. 1. The "Fix geometry" tool is also available under "modify features in place". So you don't have to create a new layer of fixed geometry every time. 2. There is also there the "check geometries" tool/plugin under the vector menu that you can use if you still find you are having problems with invalid geometry after you've run the two tools you ran here (lets you drill down and offers solutions at multiple resolutions). I find that ArcGIS and MapInfo are far less bothered by the quality of geometry than QGIS and PostGIS are. GEOS is a much higher standard clearly.

[@GISCoordinated]

Thanks for the comment. Yes you are quite right there are some other good options. I think at the end of the day it is best to try and ensure the geometry is valid at point of capture - e.g. JS API for ArcGIS you can check for self-intersecting polygons.

[@TheDuke1231]

@@GISCoordinated Couldn't agree more! I could rant for quite a while but I'll try to avoid that! It really boils down to two things .1. Training - if the data is being collected internally; and 2. Procurement - making sure that if you are commissioning data collection/creation that quality standards are a requirement.

[@beyza1205]

Thank you so much!

[@amnrsister6160]

simple but powerfull, thanks

[@scream6465]

You're the boss ! thanks

[@ErvilleRitcheBOkinlay]

Thank youu very helpful!

[@francescodifilippo6946]

Where did you find the layer Italy_CAPs? Can you share it? many thanks

[@KennyMorris-yd6wq]

TY! how do you fix "no spatial index exists for input layer"?