[Qgis-developer] About digitizing with GRASS Plugin
royroge at outlook.com
Mon Oct 19 06:05:19 PDT 2015
Il 19/10/2015 12.41, Radim Blazek ha scritto:
> It is not possible to add in QGIS a layer without a type. So when a
> new empty layer is created, a type must be chosen. The type selected
> by user is only used for the layer added to canvas/legend, the created
> vector map is empty.
Ok, I see, could it be better to disable point and line tools
while working with polygons and so on? Just an idea.
>> This can be confusing, developing some kind of hybrid between the shapefile
>> and GRASS own vector format, will also "invalidate" all
>> existing GRASS documentation about vector editing and GRASS
>> vector format. We'll need to be overly zealos to explain when
>> and how things work differently in QGIS otherwise it will be quite
>> confusing for new users.
> I don't think that it invalidates all documents about digitizing, the
> principles and the format is the same. The editing tool is different
> and it has some particularities which I'll describe in QGIS
> documentation. It is not possible to support all the flexibility of
> GRASS vector format through QGIS interface.
Well yes, sorry, not all documentation of course.
>> (2) *Attribute table editing*:
>> not able to figure out how it works, i managed
>> to edit single feature using the "Identify Features"
> Changing the values in table cells (when editing) does not work?
Opening the attribute table i get a lot of records with NULL values
I can imagine that those are for boudaries and the filled ones are
centroid records (?)
> Regarding the symbology of boundaries, I am convinced that the
> distinction between area/area
> and area/isle used in GRASS editor is useless while distinguishing of
> boundaries with topological error is essential for effective editing.
Well actually in GRASS you simply have different colors based
on the topology of boundaries, but I understand now,
given the QGIS layer limitations you explained at point (1),
that this may not be possible because QGIS layer does not
have any information about boundaries relative positions.
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