AW: [Qgis-developer] Trace edit

cmoe cmoe at
Sun Nov 28 07:26:11 EST 2010

Hi Paolo

what version of Qgis are using with the traceDigitize? I have quite
problems to reproduce the errors in trunk. What layer types are you
using (shape/postgres)? Is it possible to provide a step by step list to
reproduce it, maybe with some sample data?

> Now I keep on getting

> The geometry of the feature you just added isn't valid. Do you want to
use it anyway?

> even if I digitize very simple (and valid) triangles.
There are two explanations for this: It may be the same issue like
cadtools have with the rubberband. There was a fix of the rubberband at
the hackfest in Wroclaw. So I have to set up the minimum version to 1.7
or I have to add some backwards compatiblity. I just forgot about this.

On the other hand it is very easy with the tool to produce invalid
geometries. If you have a snapping distance of e,g, 20 pixels and your
snapping in the middle of a segment thats about 40 px long or your too
close to a vertex, the tool will snap some vertices that you are not
aware of it. This should only be true if you have set the snapping layer
to "vertex and segment". I have to think about, how to solve this.

> In fact, the cursor is always green. Any explanation?
The cursor is always green when working with traceDigitze. That's on


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