INCOSADA Spatial Data Dictionary

The purpose of this article is to describe the two different versions of our spatial data dictionary, why there are two, and who would use them.

A data dictionary is important for building information systems because it stores definitions of the business information the ministry is interested in using. Imagine us as humans trying to speak English with no common "dictionary" - we'd all use our own words for things (of course, some of us do that already anyway!) and no one would understand anyone else.

The INCOSADA Integrated Spatial Data Dictionary (ISDD) is a data dictionary that stores business definitions about spatial (geographic) features, such as silviculture opening or road. In addition, it stores technical information used to digitize each feature, such as the type of feature (line, point, polygon), the line weight and colour, etc.

Due to technological limitations in the spatial tools industry, and the huge amount of data the Ministry of Forests has in "old" spatial tool formats, we are developing two versions of the ISDD.

Background

ISDD version 1.0 was originally created by Data Administration staff in 1995, based on work done in Penticton that specified spatial feature requirements for the Forest Practices Code. The INCOSADA project developed an initial data dictionary design in early 1996. The Data Administration group improved that version by refining the database structures and significantly adding to the content over the next 1.5 years. The content of ISDD version 1.0 (we now call it "ISDD1") was made available on the ministry’s FTP site early in 1997, and has not changed since August 1997.

ISDD1 provides spatial data standards for those who are digitizing data in pre-INCOSADA IGDS-format files (e.g. Forest Cover (FC1), Tenure (TEN)).

The Evolution of the ISDD

ISDD is evolving, with both its structure and contents changing. ISDD2 (ISDD version 2) contains new spatial data requirements and removes the need for storing others, because of INCOSADA’s different file formats that take advantage of new GIS software capabilities.

For example, many of the spatial feature classes recorded in ISDD1 also contain attribute information. That is, they record not only spatial information (what kind of spatial feature it is, where it is located; e.g. polygon, lat/long), but also business details (what the object contains; e.g. Activity Treatment Unit: type of activity or treatment and when it occured).

It is not necessary for ISDD2 to embed attributes within the spatial information, since INCOSADA tools will provide the link between attribute and spatial data. Therefore, over the summer of 1997, ISDD1 was extensively examined and most attribute information was removed to create ISDD2. ISDD2 is an integral part of the INCOSADA tools, but ISDD1 will still be useful to those who have not yet updated to INCOSADA standards.

As of May 1998, several different parts of the ministry are in full swing with the Forest Development Plan template, identifying even more spatial features (and attributes). Not everything has gone into ISDD2, though: we chose to limit what went into ISDD2 from FDP, since there is a certain amount of overlapping, duplicated, or conflicting information that is being identified. Many people are still working on the identification of FDP information. Also, while the Forest Practices Code identifies new data to be collected by law, in many cases the corresponding data structures and the data collection processes have not been defined yet. These were also left out of ISDD2, and will be added when there is province-wide agreement on definitions.

The Future

The Integrated Spatial Data Dictionary will be the primary method by which the ministry distributes all our spatial data standards. We will provide this access via the world wide web, making the contents of ISDD available to Ministry of Forests staff, forest companies, forestry contractors, and the general public, through any web browser. This means coordination with current projects such as Forest Development Plan template and the Data Service Centers, incorporating spatial data standards.

ISDD2 is the link between INCOSADA software and the new spatial data files (e.g. VEG, RDS, etc.). [One problem of course is that INCOSADA tools that will work to integrate new file structures have yet to be built.]

What ISDD2 has done:

• re-structured feature classes by re-grouping them, removing redundancy, and assigning standard components;
• re-structured feature file storage, by removing redundantly stored feature classes and referenced files;
• expanded spatial standards to include linkage to attribute data and quality assurance specifications.

Details about the two versions

• ISDD v1 is in MS Access only and will be accessed via web lookup. It contains various feature class corrections and a few new feature classes for old IGDS file formats. ISDD1 will be made available to anyone such as forest companies, forestry contractors, Ministry of Forests staff, and the public. Our preferred publishing strategy is via web lookup.
• ISDD v2 will run on two platforms in different ways. The MS Access version will deliver the data dictionary only (i.e. feature classes in the new design) and will be available to anyone such as forest companies, forestry contractors, Ministry of Forests staff, and the public (via web lookup as above). The Oracle version will be integrated with INCOSADA software, and will be used for feature capture and update within the ministry (this is being developed by a consortium in a Joint Business Alliance with the ministry). The first practical prototype version of ISDD2 (both platforms - the MS Access data dictionary only, and the Oracle data dictionary plus software) is expected to be ready in June 1998. The first production version is targetted for fall 1998.

Summary

ISDD is the primary method by which the Ministry of Forests delivers its standards for spatial data design and capture. The following table summarizes the different versions of ISDD and their respective purpose.
 

More Information

If you have any questions about the ISDD versions, please contact the author. We realize the use of the two distinct versions is confusing; unfortunately that's a reality we have to live with because the spatial tools industry is still developing.

Jeremey Janzen
Data Administrator
Information Management Group
email: jeremey.janzen@gov.bc.ca