OpenGIS Consortium Technical & Management Committees
Nashua NH, USA 15-19 June 1998

Mission Report

0. Distribution List

1. Subject

One of the regular 2-monthly meetings of the technical committee, subcommittees and working groups. This most recent OGC bimonthly meetings were hosted Oracle New England Research Laboratories, a Principal Member of OGC.

2. Participants

120 attendees representing 59 organizations and 12 countries were present.

From JRC: Sargent (SAI)

3. Aim of the Meeting

Continuation of technical work devising and agreeing interface standards within the remit of the OGC. The results are 'RFPs', Requests For Proposals and adopted specifications.

4. Central Results of the Meeting

I was elected to be chairman of the Feature Identity and Relationships Working Group, newly established to push through the next OGC standardisation effort and to edit the next RFP. This is a significant honour and a position of high visibility.

5. Report of the Meeting

The OpenGIS Consortium (OGC) convenes its technical committee six times a year. The last half-day overlaps with the OGC Management Committee meeting that then takes another day after the Technical Committee finishes. I attended all four days of the Technical Committee and all of the Management Committee (by invitation).

Full reports and current technical papers, attendee lists and policy statements can be found on: http://www.opengis.org/

The technical committee meets together only for scheduling, conclusion/reporting and new generic "technology awareness" presentations. Most of the time is spent in smaller meetings of Special Interest Groups (SIGs), Working Groups (WGs) or ad hoc groups of three or four people and one Task Force (TF). The ad hoc groups are generally where the innovative thinking is done.

The following groups met, some several times:

I attended one informal meeting:

Brief Notes

These highlights are covered in more detail below.
The OGC meeting was at a hotel 5 minutes from Oracle lab. where they develop the Spatial Cartridge, Image Cartridge etc. I spoke with several Oracle people working on these. A combined spatial-image cartridge (satellite rasters) will be out in a year or so.

ISO

We had presentations for ISO TC211 Quality measures and ISO WWW Portrayal, and lots of ISO people were participating. The integrated working practices are working well. The relationship with ISO SQL-3/MM is also very good: a joint meeting is happening this week.

IMPLEMENTATIONS AND DEMONSTRATORS

In the Management Meeting (which I attended by invitation), it was disclosed that the FGDC one-off demonstration cost $120k in cash, 2 solid man-months by Allan Doyle and an estimated 6-8 man-months of technical experts from participating companies. Total cost (including man costs) to all involved must have been more than $600k.

- Conformance Testing:

ESRI, MapInfo and Oracle have already developed SQL Simple Features and are just waiting for the conformance testing process to be set up. No requests yet for OLE/COM or CORBA conformance testing. But Smallworld and eventually Laser-Scan are soon going to submit CORBA implementations. The problems here are that both OLE/COM and CORBA Simple Features have basic problems that must be fixed first though an RFC.

- Interoperability Program:

Lockheed Martin is in the process of becoming a Strategic Member ($250K annual fees), and putting up part of their facility in Gaithersburg Maryland to become OGC's first Interoperability Center. This has the initial high priority of supporting OpenGIS Conformance Testing, but will also be used for setting up demonstrations and testbed activities (e.g. Web, Java)

NOTE: OGC members below the Principal Member level will be charged a usage fee. Similar centers in Europe and Japan are envisioned, but not planned yet. Who would be an appropriate organisation to become Strategic and to host the centre in Europe ? who would want to pay 250k ecu EVERY YEAR... ?

- GIS/LIS'98 conference in Ft.Worth Texas, 8-12 Nov.98

This is the target for a large multi-vendor OGC exhibit and demonstration. They are getting a booth, with network connections between it and OGC exhibitors' booths. They will present OGC demonstrations in the booth, with hardware on loan from Sun Microsystems, and Intergraph offering Windows NT boxes and/or large NT server. It's certain that "real" OGC Simple Features interfaces for SQL will be demonstrated (ESRI, Mapinfo, Oracle).

DEVELOPMENT WORK

- Feature SIG:

I was elected to lead the new working group to write the RFP for Feature ID and Relationships, i.e. network analysis topology. This is an honour I could not refuse. If JRC cannot get its membership sorted out then I will officially be a Laser-Scan member for this purpose. This work detail should help get JRC more visibility. The hope is to have enough understanding of the issues to release an RFP in September 98 (ambitious).

- Complex Geometry:

This is a subset of the Feature SIG activity, but it's distinct from the Feature ID issues. Complex geometry means splines, arcs, and other parametric shapes, but may include geometric topology. John Herring (Oracle) is hosting a joint meeting of ISO/TC211 working group on geometry, SQL/MM working group on spatial geometry, and OGC at Oracle in Herndon Virginia THIS WEEK. Following that meeting, the OGC will work further on the geometry section of the Abstract Spec, and toward generating an RFP.

- WWW Mapping SIG:

Paul Morin from ISO/TC211 , Canada, presented the current status of ISO/TC211 work on "portrayal". This looks like a good start toward a general standard that would allow OGC to define a profile that the vendors could support. Sam Bacharach (said he was much in favor of what he saw of this. A lot more work is needed. The soonest that Allan Doyle thought he could see an OGC Portrayal RFP out, would be Jan '99.

- Coordinate Transformation WG:

Dan Specht presented a reference object model on spatial reference systems and what he thought would be the basis of an Abstract Spec volume on coordinate transformation within the OGC service architecture. Some people more familiar with the ISO/TC211 work item told him he needed to coordinate with them and build on that effort. There are a couple meetings in June & Aug, he will follow up on.

Meetings Calendar 1998

 
3-7 August  Springfield (VA) USA  Lockheed-Martin, US Army TEC
5-9 October Vienna, Austria GIPSIE and TU Vienna
7-11 December  Mountain View (CA) USA  Sun Microsystems
 

6. The Management Committee

Distributed Computing Platform (DCP) position becoming obsolete: Current issues with Simple Feature Spec implementations: OGC Interoperability Program, Lou Hecht GIS/LIS '98, Ft.Worth TX, 8-12 Nov 98 European Issues, Dave Schell Japan and NSDIPA Issues, Yamauri (?) OpenGIS Conformance Testing Program OGC OPERATIONS

7. Results from the Technical Committee working groups

Feature SIG Meeting, 15 June

Recap actions from April 98 (Reston) Feature SIG meeting

Note that there was essentially no follow-up on any of these action items since the last meeting.

Current Feature SIG meeting

D. Arctur led discussion, in Robin Fegeas and Kathy Lajoie's absence. Reviewed progress from previous meetings:

  • Feature ID motivation to be incorporated into Abstract Spec:
    •
  • Issues to be addressed in RFP:
    •  Arctur: Reviewed that the focus of feature ID discussion needs to be on interface not on structure. Also need to discuss how to address cross-platform interoperability in the RFP. Cliff Kottman suggested using RFP6 (Coverages) as template for cross-platform language.

    Adrian: Wants to distinguish between different kinds of feature ID:

  • feature handle -- local application's internal assignment

    • permanent ID -- assigned for persistent datastore

     Wants to know if version# is to be part of the ID?     Sam: we've effectively taken time out of the OGIS reference model, should we bring it in now? Relates to version ID?

    Cliff: need to support notion of multiple realms or contexts of feature IDs.

    Yaser: what services need to be provided:

  • How does a manager manage objects in a db

    • External user using remote access

    Need for update

         Adam, Sam: concerned that ID will be confused with "real world object" -- wants to add a statement in the RFP, ie, "Feature IDs can be limited to scope of feature representation"

    Adrian: Std interfaces can only be described in terms of the usage environment, ie, Cliff's "realms"

    Paul Daisey: ?where to put the metadata of scope and realm of data, … with the ID?

    Arctur: need to ensure uniqueness of IDs is enforced even for simplistically designed datastores. So if simple IDs of features from different sources are combined within a single datastore, need to ensure IDs can't clash. Does this need to be done by prefixing the feature ID with a datastore ID?

    Adrian: could be done via the feature handle, which isolates feature conflicts via local ID.

    Adrian/Sam: internal IDs (handles) on external obj's within a datastore may be mappings from a large 64byte ID to 32bit ID. If source is updated, does it need to know about mappings to compressed IDs? [DKA: I sure hope not]

    PaulD: W3C RDF addresses scope: can use a set of IDs for a small set of objects but have a way of defining scope for larger context.

    General question: what about complex geometry? After much debate, agreed to separate complex geom from feature ID & relationships RFP.

    VOTE: Assigned John Herring to update OGC Abstr Spec on complex geometry to align with ISO/TC11 work item.
    Need use cases: Adrian has a few; Paul Daisey suggests a situation calling for use case could be for feature ID statistics.

    Cliff: might we consider handling IDs for processes, not just for objects? Eg, an ID for an instance of a coordinate transformation operation? Consensus: not now!!

    VOTE: Arctur: Is it time now to start up an RFP WG for producing the Feature ID & Relns RFP? Tom Strickland moved to do this, Phil Sargent seconded. MUCH discussion about need for this already. But motion passed with no objections.

    VOTE: Paul Daisey nominated Philip Sargent as WG chair, Dave Beddoe (ESRI) seconds. Motion passes with no objection.

    Adrian: At this point, he presented details of one use case, copying features from 2 datastores into a 3rd datastore, to explore how feature IDs would help/constrain the operations. Discussion got quite detailed; Adrian will summarize and report.

    ACTIONS:

    Follow-up note on Complex Geometry, from talking with John Herring: next week in Herndon VA (22-24 June), Oracle is hosting a joint meeting on this subject with ISO/TC211, SQL/MM & OGC. Further work on complex geometry at Feature SIG will fall out from this meeting.

    WWW Mapping SIG Meeting, 16 June 1998

    Paul Morin on ISO/TC211 -- ISO 15046-17 Portrayal spec

    Schedule SC: Priorities and schedule for RFPs These to be voted on, in terms of priorities TC recommends to MC, via email poll between every other TC meeting.

    SIG/WG Reports

    How the OGC works

    The Technical Committee exists to issue RFP (Requests for Proposals) documents. These identify a small, achievable need and request companies to propose a detailed software specification. To help set a context for this work, the TC continually edits a set of documents called "The Abstract Specification".

    These RFPs, which are posted on OGC's public web site (http://www.opengis.org), request the submission of proposed detailed engineering implementation specifications for software interfaces which implement recently completed parts of OGC's OpenGIS Abstract Specification. These implementation specifications typically are written by ad hoc consortia of commercial GIS vendor companies. Out of those proposed, the TC will approve and adopt at most one.

    Interfaces that conform to OpenGIS Implementation Specifications resulting from such implementation submissions will enable diverse geoprocessing software systems to communicate directly, which will enable complex geospatial information to become an integral part of modern network-based information systems.

    RFPs usually ask for implementation specifications that will enable developers to build interfaces for software running on any of the common distributed computing platforms (DCPs), such as SQL, Java RMI, Microsoft's COM and OMG's CORBA. Different DCPs require different specifications, but OGC is designing the specifications to provide as much interoperability between DCPs as possible.

    Formal documentation of the OGC Technical Committee procedures can be found on http://www.opengis.org/techno/development.htm.

     

    Philip Sargent
    TP 262
    Centro Comune di Ricerca
    I-21020 Ispra (VA)
    Italia

    Philip.Sargent@computer.org