Ok, so we will have :
+ DataStore :
- Metadata getMetadata()
- Resource getRootResource()
- Resource findResource(String name)
+ Resource :
- Metadata getMetadata()
- Envelope getEnvelope()
+ Aggregate extends Resource :
- Collection<Resource> getResources();
+ DataSet extends Resource
+ FeatureSet extends DataSet :
- Stream<Feature> read()
- FeatureSet subset(Query)
+CoverageSet extends FeatureSet :
- to be defined
We are just mimicking the metadata model, ISO-19115 is not made to
manage datas.
it is missing of lot of aspects anyway, queries, filters, creation,
deletion, transactions...
A WMS would likely be a WMSDataStore with a root resource of type
Aggregate and children
resources of type CoverageSet for each layer of the getCapabilities.
The SV_Service would be only in the getMetadata().
Johann Sorel
On 31/07/2017 23:33, Martin Desruisseaux wrote:
I would like to bring some notes for though, but I'm not sure yet what
would be the implication for the Resource hierarchy.
Le 31/07/2017 à 14:47, johann sorel a écrit :
A Resource can be of multiple types, so far we can imagine several
subtypes :
- FeatureResource (or FeatureCollection?) for features obviously
- CoverageResource for images and OGC map services, WMS,WMTS,WCS ...
- MetadataResource (or Catalog) for services such as OGC CSW
- SensorResource for datas like NMEA or OGC SOS
This proposal defines a hierarchy based on the kind of objects (Feature,
Coverage or Metadata) returned by the Resource. But ISO 19115 section
6.1 and 6.2 rather defines the Resource hierarchy based on whether the
data were collected by the same sensor, or adhere to a common production
specification, etc. For example one "DS_Resource" subtype is
"SV_Service". In my understanding, the same "SV_Service" type would be
used for WMS, WCS, WFS, CSW, etc. regardless if the service return
Feature, Coverage or Metadata.
ISO 19115 seems to consider Feature and Coverage as DataSets components
instead than Resource sub-types. ISO 19115 does not said much about how
the relationship is established, except "The method for relating
metadata to feature and attribute instance is defined in ISO 19109". I
will check tomorrow if I can find more information.
We could add to GeoAPI the Resource hierarchy as defined by ISO 19115.
But the way to relate those resources to Feature and Coverage may have
to be an Apache SIS extension, since I didn't found a clear guidance in
OGC/ISO specifications on this topic yet.
Martin
