Inter-Agency Committee on Geomatics

Ottawa
Wednesday, December 3, 1997
09:00 - 12:30

1. Participants:
2. Introduction:
3. Report on CCOG Meeting:
4. Core Data Sets:
5. CGDI Video:
6. CGDI Data Framework:
7. Conclusions:

1. Participants:

Geomatics Canada:  Mark Corey
Denis DeGagne
Sylvan Latour
Yves Belzile
Gordon Garrard
Geological Survey:  Phylis Charlesworth 
Jean-Claude Henein
Andy Rencz
National Defence:  David McKellar
Environment Canada:  Dale Swan
Indian and Northern Affairs: Valerie Hume
Agriculture Canada:  Peter Schut
Statistics Canada:  Chris Shadbolt
Canada Post Corporation: Heather Kinsley
Dan Racicot
Health Canada:   David Lewis
Greg Sherman
University of Ottawa:  Grace Welsh
Treasury Board:  Ed Buchinski
IDON Corporation:  Doug O'Brien
Fisheries and Oceans/IACG: Tim Evangelatos (Chair & Secretary)

2. Introduction:

The interest and positive support that the IACG's CGDI initiative has been garnering is indicative of the underlying need in Canada for a geospatial data Infrastructure. Framework Data is seen as a critical component, and although the recommendations of the first workshop held last May have been receiving support, they have also raised many questions.

This second workshop was organized in order to review progress in developing the specifications of proposed core data for the CGDi Data Framework, deal with a number of related issues and questions, including terminology, that have arisen, and reaffirm that the direction of the IACG's vision for Framework Data is appropriate.

3. Report on CCOG Meeting:

In 1996 the CCOG recommended that the IACG take the lead in developing the CGDI. Mark Corey led the presentations and the discussion held at the 1997 CCOG Meeting, held recently in Regina. He reported that:

A full day was allocated to CGDI. It began with an overview presentation by Mark followed, by presentations by the leaders of the five CGDI thrusts. Denis DeGagne also spoke on the progress and specifications of the proposed "coherence data set", which is described in the following section. The video prepared under the guidance of the Center for Topological Information was also shown.

According to Mark, the CCOG congratulated the IACG on the progress achieved over the past year. The provinces and territories supported and endorsed the five thrusts and are prepared to ensure that their jurisdictions become part of the CGDI. The video was also very well received and now being used by many CCOG members to build support for GSDI in their organizations

4. Core Data Sets:

Denis DeGagne gave a detailed presentation on the data set of easy-to-identify, georeferenced, accurate and homogeneous points, proposed at the first Framework Data Workshop.  These points would be used as visual references to align and integrate geospatial data from various sources. CTI had suggested that this data set be called "The Coherence Layer", but after considerable discussion the group decided that the term "The Data Alignment Layer", which reflects the intended use of the data, should be used. The French translations is "la couche de cohéence". Denis' slides are included as Attachment #2 and should be consulted for the detailed recommendations from CTI. 

Some new aspects that Denis presented, was the recommendation that the centre of mass of small areas such as lakes and islands should be used, particularly for those areas of Canada where there are few, if any, roads. This is based upon similar applications used to register remotely sensed imagery. It was felt that such points would be easier to compute, identify, and use than river intersections. However this would not exclude the use of river intersections which still require more investigation.

Initially a simple ASCII file is being proposed, but eventually an Internet accessible database would be provided. The proposed database would allow users to extract only the data they needed, and would facilitate the addition of more accurate data, while at the same time providing a consistent and stable version of the official points in the alignment layer. He would like to see something that required little if any maintenance and acknowledged that there are many questions still to be answered. Denis underlined that with the Data Alignment Layer we are trying to solve certain specific problems and some users may require other solutions. 

Over the next several weeks CTI will draft a product description, followed by a detailed system description. Plans are to begin implementation in April 1998. Feedback from IACG and CCOG members are particularly important in this phase of developing the data set. 

During the discussion some serious misunderstanding about the use of the Data Alignment Layer surfaced. Some individuals thought that all data to be included within the CGDI "Framework" would have to be tied directly to the road intersections, or other reference points in the Data Alignment Layer, in order to ensure consistent data that could be readily integrated. However, some data is, or has been, collected to an accuracy equal to or better than that of the points in the data alignment layer and should not have to be tied to that layer. 

Dave McKellar initiated a discussion on what existing or developing standards might be suitably employed in the Data Alignment Layer and as there was no clear answer, Doug O'Brien (IDON) was asked to check the ISO TC211 work to see if it is applicable. Dave stressed that it would be foolish to move in some completely different direction and the group agreed.

5. CGDI Video:

As a number of the workshop participants had already seen the video, it was shown during the coffee break. As at CCOG, it was felt that the video was just what was needed at this time. The length and content were just about right, and it was agree that the video will be useful in helping senior bureaucrats understand what the IACG is trying to accomplish. Sylvan Latour and his team at Sherbrooke were applauded for their efforts.

6. CGDI Data Framework:

Dave McKeller gave a short presentation on the Global Information Infrastructure (GII) Framework developed by the US and Canadian military. The overall framework is based upon an advanced vision developed for the armed forces and defines all aspects of their proposed infrastructure including: Policies, Standards, Architecture, Technologies and Doctrine. It builds upon new services required by the forces, and upon a comprehensive suite of foundation and mission specific data sets to be used to provide those products and services. Dave acknowledged that the IACG needs may be quite different but he felt that the IACG could benefit form the military's progress and resources, as well as helping the IACG achieve their goals.

Dave's slides are included as Attachment #3. These include the definition and characteristics of two important terms, namely:

• Foundation - reliable, well-known secure data produced and available
• Framework - more intensified and feature specific data used to build applications, largely application dependent (may exist outside of military)

The discussions on the use of the "Data Alignment Layer" led to a modified vision of Framework Data that is illustrated in Figure 1. The vision of an overall, consistent suite of data from different sources and accuracy remains unchanged, but accurately georegistered data would not have to be tied to the directly to Data Alignment Layer.

Other discussions concerned the inclusion of other freely available data such as Digital Chart of the World (DCW), and World Vector Shoreline as part of the CGDI Core Data. Only those portions covering Canada would be used and it was felt that this data should be integrated with the Data Alignment Layer. Whether this would be a useful and cost effective thing to include was discussed at some length, but as no one could provide a definitive answer, further investigations are required. Nevertheless the group would like to have the supplementary data included with, or tied to the Data Alignment Layer.

Core Data was defined as being:

• Freely available with no copyright restrictions
• Unique
• Tied to the Geodetic Reference and/or to the Data Alignment Layer

Figure 2 illustrates the Core Data Sets and the Base Data Sets in more detail.

7. Conclusions:

The basic goals of the workshop were achieved. The progress in building the Data Alignment Layer was reviewed and the discussion of several important issues was accomplished. A few of these issues were resolved, but many new questions were raised on who will use, and benefit from the Data Alignment Layer? What else should be included with it? And how should it be used in the overall CGDI Data Framework? Further not everyone was convinced of the value of using the center of masses of small islands and lakes as part of the registration process, and some testing and demonstration of this technique is warranted.

The underlying principle of Framework Data within the CGDI has strong and growing support across Canada, but not surprisingly each step forward raises new questions. Although the group concluded that we need more insight on how to build the geospatial data infrastructure, the meeting ended with a highly positive and optimistic attitude that it was moving in the right direction.

Attachment #1

IACG - CGDI Framework Data Meeting

Wednesday, December 3, 1997
09:00 - 12:30
Room 204, 615 Booth St.

Proposed Agenda:

1. Welcome and Introductions     (Chair)
2. CGDI Video       (Denis DeGagne, CTI)
3. Report/ Recommendations on the "Test Data Set"  (Denis DeGagne, CTI)
4. Report on the CCOG Meeting in Regina   (TBD)
5. Review of the CGDI Framework Data (Terminology, Contents) 
6. Conclusions and Future Actions