Hi Martin. I'm interesting to work on 'SIS for Android' [1]. So please provide some background about it then I can start it asap.
Thanks, [1] - https://svn.apache.org/repos/asf/sis/branches/Android/ On 19 June 2014 at 21:30, Martin Desruisseaux <[email protected]> wrote: > Hello all > > The OGC meeting was hold in Geneva form June 10 to 13. We lost the last > day because of French train strike, so this email is only about June 10 > to 12. In this email, I try to explain better why an item is relevant to > Apache SIS with separated "Relevance to SIS" paragraphs. > > > Standardization process > ------------------------------------------------------------ > OGC is considering to classify their standards in 3 groups: > > * Community specification, developed outside OGC but so widely used > that they are worth to be adopted as an official OGC position. > * Provisional OGC standard, which follow OGC policy (modularization, > etc.) but have no evidence of implementation and no CITE tests. > * Full OGC standards: same as provisional except that there is strong > evidence of implementation and maturity, and CITE test exists. > > > GeoAPI is concerned by the "Provisional" versus "Full" OGC standard. For > example GeoAPI provides its own test suite (the "geoapi-conformance" > module [1]) instead than the CITE tests. This situation exists because > of the particular GeoAPI nature compared to other OGC standard, since > GeoAPI is neither an encoding standard nor a web service standard. > Closer ties between CITE tests and "geoapi-conformance" is desirable, > but we would need volunteer help for that. > > > GeoAPI > ------------------------------------------------------------ > I posted a subset of GeoAPI slides below. The most important thing is > the Feature model proposal: > > http://people.apache.org/~desruisseaux/GeoAPI/2014-06.pdf > See also GeoAPI snapshot javadoc [3] > > We had about 7 peoples in the room. We got no comment yet on the feature > model. We got a comment that explicit support for circles is needed for > user location with a mobile device in GeoXACML 3.0. GML already has > Circle and CircleByCenterPoint, but the geometry interfaces do not yet > have a Circle interface. The next ISO 19107 revision may include > circles, in which case the GeoAPI interfaces will be updated accordingly. > > *Relevance to Apache SIS:* GeoAPI interfaces are implemented directly by > Apache SIS. If there is any comments on the above Feature model, please > let us know! > > > Moving features > ------------------------------------------------------------ > The current scope of moving features is massive data exchange. Scope of > a future revision may be web service interface. The current scope has > two parts: Part I defines the XML core encoding while part II defines a > simple CSV format. The later is expected to be used most often. Those > formats can be seen as an implementation of "ISO 19141:2008 - Schema for > moving features" [2] model. The OGC Moving Features specification is > targeted for completion on December this year. > > *Relevance to Apache SIS:* we have not yet checked if the current > Feature API proposal [3] is consistent with Moving Features. This is > another area where volunteer help would be welcome. > > > Data quality and user feedbacks > ------------------------------------------------------------ > Apache SIS provides an "org.apache.sis.metadata.iso.quality" package [4] > based on standard published in 2003. The new standard revision, ISO > 19157, combines 3 older standards in a unified conceptual model. When > Apache SIS will be updated for that new standard, this is expected to > double the number of classes in the > "org.apache.sis.metadata.iso.quality" package. > > There is an other standard under development, ISO 8000, which has a yet > wider scope. ISO 8000 seems to have about 150 parts (if I understood > right), which I think would be beyond the Apache SIS scope. If I > understand right, ISO 19157 (which Apache SIS would support) could be > seen as a subset of ISO 8000. However if anyone wanted full ISO 8000 > support, I suspect that it could be the scope of a different Apache > project. > > An other data quality model is UncertML. UncertML provides some > probability distributions that can be used to express uncertainties in > positions, continue attributes, etc., but does not try to address (in my > understanding) other kind of values like confusion matrix, counting > number of conflicts, etc. They were some discussion about how to combine > UncertML with ISO 19157. > > *Relevance to Apache SIS:* we will need to update the > "org.apache.sis.metadata.iso.quality" package, but make clear that the > scope is not full data quality in ISO 8000 sense. > > > User feedbacks > ------------------------------------------------------------ > "Data quality" (ISO 19157) can be seen as a kind of metadata (ISO > 19115), and "user feedbacks" can be seen as a kind of "data quality". > The GeoViQua and CHARMe projects are experiments for complementing the > existing ISO 19157 elements with accumulated reports from data users. > The idea is to provide rankings like on the Amazon web site. This is a > different model than the current one: > > * ISO 19157 is a "producer quality model" (quality recorded by the > producer). > * GeoViQua and CHARMeare are "consumer quality model" (attempts to > post-qualify the dataset). > * An other model mentioned but not discussed is "stakeholder quality > model". > > > However the "consumer quality model" raises the issue of users as a > source of error. This issue may be reported by the ISO 19157 > "metaquality" (quality of the quality) element. One way to reduce the > problem is to iterate with the users. For example sending a request for > more information, asking same question in different ways, suggesting > that the user move to a different location, asking other users in the > area to confirm the observation, re-evaluating the quality of previous > observations as new information is made available. > > The above-cited GeoViQua project proposes QualityML as an extension of > UncertainML. QualityML is a dictionary for quality metadata encoding. > This is not yet a standard, but an experiment. > > *Relevance to Apache SIS:* we may need volunteer work for checking if > user feedbacks should be supported as an > "org.apache.sis.metadata.iso.quality" extension, maybe in an > experimental module. > > > GeoTIFF and NetCDF metadata > ------------------------------------------------------------ > A mapping from GeoTIFF tags to the "Coverage" model (a generalization of > rasters model) has been published [5]. A similar mapping from NetCDF to > "Coverage" model is under way. A draft exists, but there is still open > issues with OPeNDAP, especially their use of index for data access. > After the "NetCDF to coverage" binding, a next goal may be "ncML to GML" > (ncML is a XML encoding of NetCDF metadata. > > *Relevance to Apache SIS:* once the "NetCDF to coverage" standard is > published, Apache SIS may need to revisit its NetCDF mapping > implementation [6]. > > The European Space Agency (ESA) is working on an extension of NetCDF > standard attributes for Earth Observation products [7]. This proposal is > compliant with CF-NetCDF and NetCDF-U (uncertainty convention). Final > version is planned for July, and standardization through OGC may come > later. > > *Relevance to Apache SIS:* the mapping of Earth Observation attributes > to ISO 19115 metadata is not yet clear to me. But if a volunteer is > willing to investigate, we should augment our NetCDF mapping > implementation [6] with those Earth Observation attributes. > > > GML in JPEG2000 > ------------------------------------------------------------ > GMLJP2 version 2.0 is under work. The new specification will clarify > some GMLJP2 1.0 ambiguities (e.g. axis order), and may add support for > "georeferenceable" [8] images (not to be confused with "georeferenced" > images, which are already supported). They were also a request for > motion image annotations. > > > (Transactional) Web Coverage Service > ------------------------------------------------------------ > WCS-t contains 3 operations: insert, delete and update. The "update" > operation is the hard one to define. Work is still going on the later. > As a side-note, some peoples expressed the need to be able to determine > if a bounding box contains any non-null value before to request a > coverage (raster) in that area. The goal is to reduce the transfer size. > > Some peoples are investigating JPEG 2000 Interactive Protocol (JPIP) for > streaming of coverages with reduced band width usage. An other aspect > under study is asynchronous access to WCS coverages via FTP or on DVD > (user noticed when ready). > > > Linked data > ------------------------------------------------------------ > While I'm not aware of an OGC standard specifically related to linked > data, OGC is thinking about this long-term tendency. The current World > Wide Web hyperlinks focus on "document about things". The Linked Data > approach rather focuses about thing themselves. This will require things > to have a unique and persistent identifiers. > > *Relevance to Apache SIS:* SIS already tries to prepare itself with the > IdentifiedObject interface [9]. We do not know yet if the SIS approach > will work well, since I'm not aware of feedback yet. > > > Mobile location services (MLS), a.k.a. "Mass market" > ------------------------------------------------------------ > The "mass market" working group has been renamed Mobile Location > Services (MLS) domain working group. > > *Relevance to Apache SIS:* we have an orphan "SIS for Android" branch > [10]. If we get a volunteer for maintaining that branch, we may need to > follow Mobile Location Services activity in order to apply relevant > recommendations to our branch. > > Martin > > > [1] http://www.geoapi.org/geoapi-conformance/index.html > [2] > > http://www.iso.org/iso/home/store/catalogue_tc/catalogue_detail.htm?csnumber=41445 > [3] > > http://www.geoapi.org/snapshot/javadoc/org/opengis/feature/package-summary.html > [4] > > http://sis.apache.org/apidocs/org/apache/sis/metadata/iso/quality/package-summary.html > [5] https://portal.opengeospatial.org/files/?artifact_id=54813 > [6] > > http://sis.apache.org/apidocs/org/apache/sis/storage/netcdf/AttributeNames.html > [7] > http://wiki.services.eoportal.org/tiki-index.php?page=Prod-Trees+Resources > [8] > > http://www.geoapi.org/snapshot/javadoc/org/opengis/metadata/spatial/Georeferenceable.html > [9] http://sis.apache.org/apidocs/org/apache/sis/xml/IdentifiedObject.html > [10] https://svn.apache.org/repos/asf/sis/branches/Android/ > > -- Charitha Madusanka Linkdin : http://www.linkedin.com/pub/charith-madusanka/1a/508/42a Twitter : http://twitter.com/#!/charithccmc
