[Qgis-user] Query cross-table "similar" time stamps?

[Bernd Vogelgesang]

Uupss, wrong link. That was a similar question from 7 years ago ;)

https://gis.stackexchange.com/q/322544/8202

Bernd

Am 15.05.19 um 13:27 schrieb Bernd Vogelgesang:
> Hi folks,
> I'm sure there must be some "easy" solution, but hours of searching
> provided no examples I could learn from to develop a solution:
>
> I have a point layer of bird observations and a GPS-track recorded while
> observing the birds in an area.
> For the interpretation of the findings it would be good to easily find
> out, from which position the recorded observation was taken.
>
> My idea was to compare the timestamp of the bird point with the
> timestamps of the track points, but I run into huge obstacles right at
> start:
> I know that I "could" query across layers by the expression aggregate().
> Unfortunately, the docs on that is so sparse, that I have not the
> slightest idea how to even start with that
> (https://docs.qgis.org/testing/en/docs/user_manual/working_with_vector/expression.html?highlight=expression#aggregates-functions)
>
>
> Ok, in case I could find out how to properly use aggregate, how do I
> best compare those time stamps?
> The layers derive from gpx-files and QGIS identifies the time tag as
> QDateTime.
>
> As it is not very likely that a bird observation was recorded at the
> exact same time as a track point was generated, there is no way to
> actually compare the values, cause the bird time value will always lie
> in between two track point values.
> What kind of query can be used to identify those two trackpoints ?
>
> In short: How can I identify/highligt/mark track points that have a
> timestamp close the selected point in another layer?
>
> I already created a question on this on gis stackexchange with a
> screenshot,but no reactions so far.
> https://gis.stackexchange.com/q/30708/8202
>
> Thankful for any hint
> Bernd
>
> _______________________________________________
> 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