[GRASS-user] v.out.ogr and Date fields

[Markus Metz]

On Wed, Nov 6, 2019 at 3:01 PM Markus Neteler <neteler at osgeo.org> wrote:
>
> Hi Daniel,
>
> On Mon, Nov 4, 2019 at 12:23 PM Daniel McInerney
> <daniel.o.mcinerney at gmail.com> wrote:
> >
> > Hi List,
> >
> > As part of a workflow, we are importing ESRI Shapefiles into GRASS so
> > that we can manage the vector topology, before re-exporting the vectors
> > back to an ESRI Shapefile. However, we noticed that the date fields are
> > being converted from a field of type Date to type String.

Indeed, this happens in v.out.ogr, should be easy to fix. Can you create a
ticket just as a reminder?
>
> AFAIK this is how SQLite handles it internally but the GRASS DBMI
> driver should take care of it to keep it in date format.

This has nothing to do with the sqlite driver.

Markus M

>
>
> > Hopefully the
> > following steps will demonstrate the issue:
> >
> > The input Shapefile is scdb_date, with a date field called 'BA_DATE':
> >
> >  >ogrinfo -so -al scdb_date.shp | grep BA_DATE
> > BA_DATE: Date (10.0)
> >
> > After importing into GRASS using v.in.ogr, the field is still of type
> > DATE (although the length has increased to 20):
> >
> >  >db.describe scdb_date | grep -A 5 BA_DATE
> > column:BA_DATE
> > description:
> > type:DATE
> > len:20
> > scale:0
> > precision:0
> >
> > However, when I export the vector (scdb_date) back to an ESRI Shapefile
> > using v.out.ogr, the BA_DATE is converted to a String:
> >
> > v.out.ogr input=scdb_date output=scdb_date_export.shp
> > format='ESRI_Shapefile'
> >
> >  >ogrinfo -so -al scdb_date_export.shp | grep 'BA_DATE'
> > BA_DATE: String (20.0)
>
> Probably the date detection failed in the grass-sqlite driver?
> Could it be an encoding problem?
>
> > I tried exporting to a GeoPackage, but the issue persists. While, we can
> > still overcome this issue using ogr and SQL, I am wondering if is there
> > a flag or option in v.out.ogr that I am overlooking that would maintain
> > the fields of type Date or is there something else that I should
consider?
>
> As this is unexpected could you make a small data sample available to
> easier reproduction?
>
> thanks
> Markus
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