[Qgis-developer] morph delimited-text-provider to generic table-provider?

[Neumann, Andreas]

Hi, 

I would welcome an "easier" way to open Point or WKT data from formats
that do not store geometries natively, as you propose. Thanks for
bringing it to the table, Raymond and Richard! 

My suggestion would be to enhance the existing OGR "Add vector layer"
dialog with an option to choose columns to be used for geometry
creation. This way we don't have to "misuse" the delimited text layer
loader for other formats and the user could open the data all in one
step, without the need for postprocessing. OGR VRT provides all we need
to create geometries from columns - see http://www.gdal.org/drv_vrt.html


The drawback is that it would work only for OGR formats, not for all the
other databases. But I would assume that people using databases are
skilled enough to be able to use QGIS virtual layers, views, etc. to
build geometries from their databases. 

Greetings,
Andreas 

On 2016-07-09 11:00, Richard Duivenvoorde wrote:

> Hi Devs,
> 
> Raymond Nijssen had an (I think) intriguing idea:
> 
> QGIS can open different types of table-data: dbf, excel etc etc
> 
> But if the excel contains an x,y,wkt column, you have to save it to
> csv/tsv first, to be able to use the delimited-text-provider to open it
> as a layer.
> 
> His idea: can't we use the delimited-text-provider for all tables that
> are open in QGIS immediately?
> 
> Had a look into the code
> 
> https://github.com/qgis/QGIS/blob/master/src/providers/delimitedtext/qgsdelimitedtextfile.cpp#L583
> 
> which 'just' looks like a QTextStream:
> 
> https://github.com/qgis/QGIS/blob/master/src/providers/delimitedtext/qgsdelimitedtextfile.h#L352
> 
> And according to this:
> https://forum.qt.io/topic/63310/how-to-save-a-treeview-as-csv-file-in-qt
> 
> It is easy to create a textstream from QModel (in which we have the data
> I think???)...
> 
> So Question:
> - (to devs): would this indeed be doable/easy?
> - (to UI's): should the Delimited Text File dialog be updated then (or
> only with a 'open excisting table button'?
> - should we rename the provider to 'table' provider.
> 
> Comments/Opinions?
> 
> Regards,
> 
> Richard Duivenvoorde
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