[Qgis-user] Repairing Topology Errors

[Springfield Harrison]

Hello Group,

        I have been manually creating a few simple polygons, always intending to have no gaps, slivers or overlaps.  To do this I use snapping and occasionally the Autotrace feature.

        However, when I run the topology checker, it often flags a variety of errors although I am careful to create polygons by only snapping to existing vertices of adjacent polygons.  It does a great job of finding the errors, but I can find no instructions on methodology for repairing them.

        Any suggesting on repairing topology errors easily?

                 Thank you, Cheers . . . . . . . . Spring Harrison



At 03-02-2016 07:51 Wednesday, Carlos Cerdán wrote:

Hi Springfield:

I've had similar trouble some time ago, as a QGIS beginner user. Previous given advices are for not too-beginner users, but I think my experience can be useful for the list (or even for you?):

That time my error was my Snapping options: I had selected two or three layers and it was selected the "avoid intersections" option, then, when I added new digitized polygons, they were splitted or deleted (as you tell) because new polygons were intersecting marked layers in snapping options. It fixed when new digitizing shape was the one marked (of course to avoid intersections between her elements) .

Yes it was something simple, my foul. Is it not same trouble?. If so, Check it in "Configuration --> Snapping options --> Change the Self-assembling mode to "advanced" and be sure that "avoid intersections" is marked in your target layer only.

Cheers,

Carlos Cerdán

2016-02-02 20:57 GMT-05:00 Springfield Harrison <stellar...@gmail.com >:

Hello Group,

        Am using QGIS 2.10.1 and have done so without significant problems for many months. I am attempting to create simple polygons in a shapefile by direct vertex entry or copying polygons from another shapefile layer and pasting them into the active layer.

        In almost every case, these features disappear. There is an entity entry in the attribute table but there are no polygons created. In one case a polygon was created but it was not the shape that I digitized; no more polygons could be created although the process for doing so appears to be working. No error messages were created. The CRS for the project and the shapefile are the same.

        The shapefile can be opened in another GIS but has no content.

       Â

        Here are some product details: QGIS version 2.10.1-Pisa QGIS code revision d20c5b7

        Thanks very much for any help you can render, Cheers . . . . . . . . Springfield Harrison

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