[Qgis-user] Geopackage decimal lenght and precision not available

[Fernando M. Roxo da Motta]

On Wed, 26 Feb 2020 09:27:18 -0500, Patrick St-Hilaire
<ps.vlachute at gmail.com> wrote:


> I solved the problem with this function
> 
> round("ELEV",2)

  Beware of the floating points, be it single, double, quad, or any
other precision.   This solution you used may produce results (e.g.)
only when printing this or converting to a character sequence of some
sort.

  Depending on the truncated value it can be impossible to represent as
an "exact" number due to mantissa normalization afterwards, giving you a
"periodic tithes" (is this the name in English?), where a decimal
(binary in this case) pattern is repeated ad infinitum.

  Any math operation after this can imply in extra rounding errors.


  Floating point is a kind of untameable beast.  ;)

> 
> Le mar. 25 févr. 2020 à 14:55, Bernd Vogelgesang
> <bernd.vogelgesang at gmx.de> a écrit :
> 
> > As far as I know sqlite-based formats do not need such settings. I
> > think the need to do so in Shape files derives from those ancient
> > times when each byte of memory was so expensive, that you had to
> > squeeze your data to the lowest footprint possible.
> > Am 25.02.20 um 20:23 schrieb Patrick St-Hilaire:
> >
> > Hi,
> >
> > I started using geopackage instead of shapefile, but I can't use
> > length and precision decimal with geopackage. Is this normal? See
> > image screenshot
> >
> > It's in french language
> >
> > I use the 3.4.5 Qgis version.
> >
> >
> >
> > _______________________________________________
> > Qgis-user mailing listQgis-user at lists.osgeo.org
> > List info: https://lists.osgeo.org/mailman/listinfo/qgis-user
> > Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user
> >
> > _______________________________________________
> > Qgis-user mailing list
> > Qgis-user at lists.osgeo.org
> > List info: https://lists.osgeo.org/mailman/listinfo/qgis-user
> > Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user  








  Roxo

-- 
---------------- Non luctari, ludare -------------------+ WYSIWYG
Fernando M. Roxo da Motta <petro at roxo.org>              | Editor?
Except where explicitly stated I speak on my own behalf.|  VI !!
                PU5RXO                                  | I see text,
------------ Quis custodiet ipsos custodes?-------------+ I get text!