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<div class="moz-cite-prefix">On 11/29/2012 03:06 PM, Nathan Woodrow
wrote:<br>
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cite="mid:CAAi8Yg81bzNY6-uD0SnbStV0zZbQYz8buE5f3Psg0VjsBzttwg@mail.gmail.com"
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<div>Hey,</div>
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Honestly I find that a pain in the neck, from a users point of
view and from a developer point of view. From a users point of
view you now have to have a tools that supports styling points,
regions, lines all at the same time, it also makes processing
harder because you have to check the geometry type before doing
certain operations.</blockquote>
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cite="mid:CAAi8Yg81bzNY6-uD0SnbStV0zZbQYz8buE5f3Psg0VjsBzttwg@mail.gmail.com"
type="cite">
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<div>From a developer point of view I think it can make things
hard because you have to check feature by feature what kind
geometry you are dealing with before working on it, have you got
a 0 length line or a point because length of a point is 0?. At
the moment we just open the layer, check the type and select the
correct methods.</div>
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Aren't you mixing up multiple geometry columns and type safety? I'm
not talking about different geometry types in one column, but in
different columns, so it should always be clear, from a certain
combination layer/column, which tools/actions are available.<br>
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cite="mid:CAAi8Yg81bzNY6-uD0SnbStV0zZbQYz8buE5f3Psg0VjsBzttwg@mail.gmail.com"
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<div>MapInfo does this and I always found it caused more problems
then it's worth IMO. Although postgres and spatialite support
storing different geometry types in the same table I have seen
it as bad practice. If you do happen to have a layer with say
regions and points for building footprints, you can put the
layer twice in the geometry_columns table with a different
geometry type and QGIS will pick it up as a different layer,
then you can just set the zoom levels on each layer.</div>
</blockquote>
My problem now is, that I need to use different geometries for the
same feature from a plugin. As the database is sometimes really
slow, I'd prefer to fetch just one table with the geometries in
several columns. This way, I also would not have to join the two or
three tables again in a plugin (it's error prone and slower the
database could handle this)<br>
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cite="mid:CAAi8Yg81bzNY6-uD0SnbStV0zZbQYz8buE5f3Psg0VjsBzttwg@mail.gmail.com"
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<div>They are my thoughts anyway.</div>
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<div>- Nathan</div>
<div class="gmail_extra"><br>
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<div class="gmail_quote">On Thu, Nov 29, 2012 at 11:55 PM,
Matthias Kuhn <span dir="ltr"><<a moz-do-not-send="true"
href="mailto:matthias.kuhn@gmx.ch" target="_blank">matthias.kuhn@gmx.ch</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">Hi,<br>
<br>
Why is not more than one geometry column per layer
supported? Would it be hard to support more than one
geometry column (and set one as the default to be
displayed)?<br>
It would certainly make some tasks easier and maybe could be
used for level of detail, related to the current zoom level.<br>
<br>
There was recently a discussion on this list about
spatialite as default layer type and spatialite would
support this, as does postgres.<br>
<br>
Regards,<br>
Matthias<br>
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</blockquote>
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