Hi Martin, Has anyone volunteered to take the lead on NetCDF to ISO formalization within the context of OGC?
Please note that we have moved off the geo-ide wiki and on to an esip wiki for ongoing discussing and changes for ACDD. http://wiki.esipfed.org/index.php/Category:Attribute_Conventions_Dataset_Discovery (See outdated reference - http://sis.apache.org/apidocs/org/apache/sis/storage/netcdf/package-summary.html ). Thanks for the update, Dave David Neufeld Information Services Division CIRES Team Lead NGDC / NOAA [email protected] On Tue, Mar 25, 2014 at 4:21 PM, Martin Desruisseaux < [email protected]> wrote: > Hello all > > An OGC meeting is going on right now in Arlington. The meeting is not > yet over, but there is a summary of some points discussed so far: > > Web Coverage Services (WCS) > ------------------------------------------------- > A specification mapping GeoTIFF tags to standards elements (ISO) has > been adopted recently. Such GeoTIFF-ISO mapping is similar to the > NetCDF-ISO mapping defined by NOAA. Apache SIS already implements the > NetCDF-ISO mapping [1], we should also implement the GeoTIFF-ISO mapping > using that document. Note that this specification is not about the > GeoTIFF format itself, however there is some talk about whether OGC > should also write a specification for it. In the current state, the > community maintaining the GeoTIFF specification is somewhat informal. > > Other data specification under work are NetCDF and JPEG2000. The > NetCDF-ISO mapping currently implemented by SIS is based on NOAA > documentation. If OGC defines formally the mapping in a specification, > we should probably update SIS accordingly. > > Above paragraphs are about "data". On the "services" side, recently > adopted specifications extending the core are: > > - CRS > - range subsetting > - scaling > - interpolation (often used together with scaling, but not necessarily) > > The meteorological-oceanographic working group said that the CRS and > range subsetting extensions worked well for them. However an Earth > Observation and meteorological-oceanographic profiles of WCS may still > be needed for other reasons, to be discussed in the "MetOcean" section > below in this email. > > A public wiki is at [2]. > > > > Transactional Web Coverage Services (WCS-T) > ------------------------------------------------- > WCS-T 2.0 is a rewrite of WCS-T 1.4 without upward compatibility - the > changes are major. WCS-T purpose is to insert, update and delete WCS > coverage offerings. Specification for insert and delete operations are > done, update operation is in progress. The difficulty for the update > operation is to specify the criterion for determining if an update is > allowed or not (e.g. replacing a 3-banded image by a 1-banded image > should probably not be allowed). > > > > Web Processing Service (WPS) > ------------------------------------------------- > A WPS 2 specification is under way. WPS 2 improvements compared to WPS 1 > are: > > * Better support for process discovery > * Improved execution management (long running processes, ability to > delete a running job) > * Better support for synchronous / asynchronous execution > > A specification draft for public comment is expected by the end of April. > > > > Meteorological-oceanographic group (MetOcean) > ------------------------------------------------- > MetOcean discussed about the extensions they wish to bring to WCS. > Rational for extensions are related to data shapes: GRIDS, time series, > cross sections, point collections (e.g. observations), vertical profiles > (e.g. ascents), trajectories. The group emphases on the needs for > sub-settings on the 4 axes, probably 5 axes in the future where the > fifth axis would be "ensemble" (e.g. probability, discussed below). > Keeping in mind that MetOcean uses two time axis (forecast time, model > run reference time), we have a potential for 6 dimensional coverages. > The group emphases also on slice, trim and sub-setting operations (e.g. > trim X, trim Y, slice Z = horizontal view). > > Some extensions needed: > > * Slice and trim requested in other CRS than the source data CRS. > * Want to advertise validity times for coverage data availability. > * Challenge: create 3D/4D grid from irregular grids with missing data. > * Needs to group coverages by collections (other amount of coverages > is unmanageable) with their own metadata. Note that the need to > define collection of coverages is probably a wider than the MetOcean > domain. Generalization will be investigated. > * Custom WCS operations: DescribeCoverageCollection, GetCorridorCoverage. > > An OGC document is hoped for the end of this year. > > The group provided some patterns of data extraction. For example > extracting vertical profile data for a trajectory (marine example: > sonar) = trim operation expressed in the CRS of the trajectory. The > group had a discussion about vertical CRS of the kind "pressure in hPa > relative to a changing datum (a pressure surface)". The action for now > is to take a closer look to ISO 19111-2 (parametric CRS). I think that > Apache SIS too should take a closer look to ISO 19111-2. > > The MetOcean group presented "ensemble forecasts": producing more than > 20 parallel forecasts based on original observations in order detect > "butterfly effect". Some statistical numbers of interest are quartile > values, decile values, 95% and 5% percentile values, mean and mode. Open > question is: can those needs be adressed by the NetCDF-Uncertainty > extension? > > The MetOcean group has a projects on GitHub [3] providing the following > resources: > > * World weather symbols, as SVG or PNG files. > * WMO Regional Associations GeoJSON. > * WMO core metadata profile 1.3. They provide an application > performing validation for a profile of ISO 19115 metadata. > > The last point is related to Apache SIS, since we implement ISO 19115. I > will create a "Provides a meterological profile of ISO 19115" JIRA task. > Since I think there is an other Apache project related to climate, maybe > there is an opportunity to contact each other here? > > > > Big data > ------------------------------------------------- > Big data has been defined as the analysis on multi-dimensional arrays of > size several orders of magnitude above engine's main memory. A > discussion working group has been formed for investigating possible > issues with OGC specifications for achieving this goal. Chairs have been > nominated. As a side note, the European Space Agency (ESA) organizes a > conference on big data from space on November 12-14th, 2014 in Fracati, > Italy. > > > > Moving features > ------------------------------------------------- > A reference implementation named "Mobmap" has been shown. This > implementation run on Chrome browser and uses CSV files (points only) as > inputs. They were discussion about using NetCDF as a more efficient > binary storage format, but there is a difficulty in complying to the > NetCDF "trajectory" convention. An alternative could be to take some > liberties regarding the NetCDF trajectory convention, but this is > something that peoples would prefer to avoid. > > The specification had only minor editions, and now includes the use case > provided by Nadeem Anjum on this mailing list. A final version of Moving > Feature specification is expected for December. > > They were an interesting discussion about JSon being - as surprisingly > as it may seem - more verbose than XML for data like the Moving Feature > ones, because of massive repetition of keywords. I'm not a JSon expert > so I can not elaborate... > > > > CITE Tests (Team engine): > ------------------------------------------------- > The "Team engine" is the testing framework at OGC. It is different than > the "GeoAPI-conformance" module that we use for Apache SIS. OGC is > working on making Team Engine easier to use - currently it has been > reported that an expert needs 2.5 hours to configure and run tests. It > is too early for Apache SIS to use Team Engine, since we do not yet > implement web services. When we will start looking at CITE, ideally I > would like to see if some CITE-GeoAPI integration are possible. > > > > Miscellaneous > ------------------------------------------------- > Some related initiatives mentioned in the meeting are: > > * Integrated Ocean Observing System (IOOS) [4] > * Integrated Justice Information System (IJIS) > * WMO Climate Data Management System Specification (CDMS) > > They were also a mention about recent and coming discussion in other > organizations about whether we should keep leap second. The > International Atomic Time (TAI) currently differs from Coordinated > Universal Time (UTC) by 35 seconds due to leap seconds added in the last > decades. Some organizations want to suppress leap seconds. No decision > has been taken yet. Of course the decision does not depend on OGC, but > opinions are collected. > > OGC is still experimenting ways to publish their specification as web > pages. A prototype is available for the GeoPackage specification. > However there is not yet a policy for allowing external projects - like > Apache SIS - to provide links to a stable anchor of OGC specifications. > For example if Apache SIS wants to link to a specific clause of an OGC > specification, whether this will be possible is still an open question. > > Martin > > > [1] > > http://sis.apache.org/apidocs/org/apache/sis/storage/netcdf/AttributeNames.html > [2] http://external.opengeospatial.org/twiki_public/CoveragesDWG/ > [3] https://github.com/OGCMetOceanDWG > [4] http://www.ioos.noaa.gov/ > >
