[Qgis-user] Micro-Geometry Problems

[Gabriel De Luca]

About how to remedy these situations, you can use the v.clean GRASS
provider algorithm, selecting the snap cleaning tool.

Kind Regards,

Gabriel

El mié., 15 de ene. de 2020 a la(s) 16:10, Gabriel De Luca (
pablogabrieldeluca at gmail.com) escribió:

> When digitizing, coordinates are taken from the canvas and stored to the
> layer. If the canvas (project) CRS is not the same as the layer CRS, a
> transformation and/or conversion must be done between the taken and stored
> coordinates. That transformation and/or conversion performed between the
> previous vertex to be rendered, and the rendered coordinate digitized to be
> stored, may lead a round trip error.
>
> If you are digitizing from a canvas CRS to the same layer CRS, and
> snapping to vertex, I think that you will not see any difference between
> both vertices.
>
> If you are snapping to intersections, you can see a difference also
> working in the same CRS for the canvas and the layer, because an
> intersection calculated coordinate may not be a rational number and at some
> decimal place it must be truncated.
>
> I don't know if any rendering option could truncate the coordinate of a
> vertex when rendering it, so when snapping to that vertex (in the same CRS
> for the canvas and the layer) could return a truncated coordinate for the
> digitized vertex.
>
> El mar., 14 de ene. de 2020 a la(s) 18:59, <smiller192 at cfl.rr.com>
> escribió:
>
>> All-
>>
>>
>>
>> I have digitized a land use/land cover layer as individual polygons.  The
>> snap options were used and, for most vertices, the snap was precise.  A
>> vertex in polygon A has a precise match to a vertex in neighboring polygon
>> B.
>>
>>
>>
>> But in 582 out of 2799 polygons, there are mis-matches in adjoining
>> vertices that are only evident if you zoom into the layer at a
>> magnification (i.e., a scale) of from 20000:1 to 40000 to 1.  I have spent
>> a couple of weeks trying to remedy these by hand using the Vertex Tool and
>> other means.  My question is this: is there an automated way in QIS to
>> detect and remedy these situations?
>>
>>
>>
>> Thanks,
>>
>> Steve Miler
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