You can have a look at that documentation page, and of course the WFS 2.0
specification. I bashed out the API with Gabriel for geogit - since it is
not in common use yet if you find any pragmatic tweaks are needed please
bring it on.
Note that WFS traditionally splits general query stuff (Filter with
Expression) and selection query stuff (FeatureId and now Revision). We slam
the two together in GeoTools in a complete pragmatic violation of spec :)
As a result you should be able to use some of the Revision
"latest","next","previous" functionality with a BBOX.
But yeah read the spec as it is bit more useful than my implementation
notes for Java developers.
Aside: If your data model is actually timestamp based then it is easy to
combine temporal and spatial filter functions (as that is the normal WFS
2.0 intended use).
Jody Garnett
On Fri, Aug 29, 2014 at 10:02 AM, Jim Hughes <jn...@ccri.com> wrote:
> Jody,
>
> Yes, we have our own FeatureStore (this is for GeoMesa). I'm actually
> interested in the most recent 'ping'. That said, using revisions may be
> sufficient since I'd imagine input would be in timestamp order. (Well,
> *most* of the time.)
>
> With the idea of the revision, I suppose I'm wondering if there's a way to
> specify a query which would return points
> 1) in a bbox (or satisfying a more general topological predicate)
> 2) only if they are latest revision (or time)
> and
> 3) satisfying any additional attribute filters.
>
> At the moment, it sounds like one could get a list of simple features for
> #1 and #3, build a list of ids, and query again for latest revisions to
> satisfy 2. Those simple features would then need to be filtered by 1 and 3
> again.
>
> Whew... I don't find this to be an easy technical feature, but it seems
> like an attractive feature. (For instance, the state of Virginia went to a
> deal of trouble to set up a web-app where you can could see where snow
> plows were after a snowstorm.)
>
> Thoughts?
>
> Jim
>
>
> On 08/28/2014 04:54 PM, Jody Garnett wrote:
>
> Did you introduce your own FeatureStore? Or are you using one of the
> existing ones ....
>
> The WFS 2.0 specification introduced a bunch of new abilities for Filter
> - including the concept of Revisions.
>
> I assume you actually want to query the most recent "edit" rather than
> the most recent date?
>
> There are two sets of functions:
>
> * Temporal functions included in ECQL (like BEFORE and AFTER)
> * FeatureId can now consist of two parts a FeatureId and a RevisionId.
> Options exist for fetching the "history" of a FeatureId, the default is to
> obtain the most recent revision. As far as I know this was implemented as
> an experiment for GeoGig but has not appeared in any stable GeoTools plugin
> ... yet.
>
> For more information see:
>
> *
> http://docs.geotools.org/latest/userguide/library/opengis/filter.html#temporal
> *
> http://docs.geotools.org/latest/userguide/library/opengis/filter.html#identifer
>
> --
> Jody Garnett
>
> On 28 August 2014 at 12:49:15 pm, Jim Hughes (jn...@ccri.com) wrote:
>
> Hi all,
>
> Two questions:
>
> Suppose one were using a GeoTools FeatureStore to manage the location
> and times of things. 1) Does there exist a natural way using an ECQL
> filter and/or a GeoTools query to ask for the most recent location of
> the each thing?
>
> If one didn't care about the previous locations, I could imagine
> updating the location of each feature as new data streams in. 2) Given
> the idea of adding and modifying a feature, is there a standard way to
> 'add-modifying-if-necessary' features to a FeatureStore?
>
> As a user of the GeoTools api, it seems like one could go to some
> lengths to roll this kind of behavior by first querying by attribute
> (say by serial number) or by id and then updating the entry. I suppose
> I'm curious if there's currently a more direct way.
>
> Thanks,
>
> Jim
>
>
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