Re: [Qgis-user] Geopackage decimal lenght and precision not available
On Wed, 26 Feb 2020 09:27:18 -0500, Patrick St-Hilaire
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
> 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.
> >
> >
> >
> > ___
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Roxo
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Re: [Qgis-user] Geopackage decimal lenght and precision not available
I solved the problem with this function
round("ELEV",2)
Le mar. 25 févr. 2020 à 14:55, Bernd Vogelgesang
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-u...@lists.osgeo.org
> List info: https://lists.osgeo.org/mailman/listinfo/qgis-user
> Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user
>
> ___
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> Qgis-user@lists.osgeo.org
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> Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user
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Re: [Qgis-user] Geopackage decimal lenght and precision not available
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 list Qgis-user@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@lists.osgeo.org List info: https://lists.osgeo.org/mailman/listinfo/qgis-user Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user
Re: [Qgis-user] Geopackage decimal lenght and precision not available
Hi, Same thing on my version. It is therefore in the file specification and cannot be changed. In this case, the decimal will be a double. You should have a 15 to 17 significant decimal precision. DOUBLE, REAL 64-bit IEEE floating point number. Stored as SQLite REAL. http://www.geopackage.org/spec/ Nicolas On 2020-02-25 2:23 p.m., Patrick St-Hilaire wrote: 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 list Qgis-user@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@lists.osgeo.org List info: https://lists.osgeo.org/mailman/listinfo/qgis-user Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user
[Qgis-user] Geopackage decimal lenght and precision not available
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 list Qgis-user@lists.osgeo.org List info: https://lists.osgeo.org/mailman/listinfo/qgis-user Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user
