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
<mailto: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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