The Relationship of Geomatics Standards to ICE in ECDIS Ice in ECDIS Workshop June 1 st, 2000 St John’s NFLD, C. D. O’Brien, IDON Technologies

Background HFor the past twenty years, many organizations have applied computer and information technology to assist in cartography, hydrography, geology, urban planning and other geographically related application areas. HAt first individual organizations developed their own computer based systems to assist them in their existing procedures. This was primarily the collection of data and the creation of paper oriented products. This was the era of computer assisted cartography.

Commonality of Tasks HOver time the commonality between the tasks being performed in different organizations was recognized. HManufacturers developed systems that were flexible to satisfy each organizations particular need. From a manufacturer's point of view this was compatibility since the same equipment could be used for many purposes or by many businesses. HOf course, the equipment of different manufacturers was incompatible, but there existed a level of compatibility if an agency used a single equipment supplier. For many areas of use this represents the current situation.

Captive markets  Certain Geographic Information System (GIS) equipment manufacturers have dominated different market areas. This has led to a locking-in of clients to particular systems. HVertical markets resulted. Data would have to be re- worked to be used in different applications. HFrom a data producer's point of view there was no standardization at all because data could not be published in a universally understood form.

Islands of Incompatibility HThere is no shortage of standards. Many agencies and companies have developed their own proprietary standards. HSome are in wide use, whereas others have very narrow applicability. HStandards limited to particular application domains are actually barriers rather than aids in fostering interchange. They create "islands of incompatibility".

Application Area Standards HStandards did develop within organizations. HIf the organization was influential, it tried to convince others within its community of use, to follow the standard. HThis led to a number of different application area- specific standards and an isolationism, which discourages the reuse of data.

What Standards are Needed? HEach application area had its own view of what standards were needed. Much like the blind men viewing an elephant who all saw the elephant differently.

Standards as Barriers HMany countries and organizations do not adopt global standards. There are only two standard voltages ( ) and (220 to 240) so there is only a need for two electrical plugs.  However many countries have different plug designs. This was originally intended to protect markets, but it ended up limiting trade. Some groups don’t want compatible standards!

HA number of different standardization developments are underway both internationally and within various nations addressing the exchange of geographic information. HIn fact, one may say that there are too many standards efforts and not enough standardization. HA wide choice of standards results in limited use of each. The greater the range of possibilities, the more unlikely that two systems share a common exchange "language". Too Many Standards

HFacsimile was invented by a Scotsman over 100 years ago, yet the technology had few users up to the mid- 1970s. HInteroperability was limited to equipment produced by the same manufacturer. HWhen the ITU-T / CCITT standardized facsimile so that all machines could interact, the market experienced tremendous growth. What happened to Fax

Explosion of growth zThe field of Geographic Information Systems is poised for an explosion of growth. z Almost everything is in some way geospatial. zConventional databases are including spatial referencing, and everything from accounting systems to word processors are including "Map" type data.

DX 87, DX90, S57 HIn the late 1980's the International Hydrographic Organization began the development of an exchange standard for nautical chart data. HThe initial standard, DX 87, provided a method of exchanging basic cartographic line work, with some objects.  Gradually this standard has been improved as DX 90 and then S-57 to address all of the information needed for an electronic chart.

S-57 and S-52 HS-57 is an International Hydrographic Organization standard for Hydrographic chart data. HIt consists of an Exchange Standard, an Object Catalogue, and a Product Specification for Electronic Navigational Charts (ENCs). HS-52 is a complementary standard that defines the performance of an ECDIS system. HIt includes a presentation library speciication. HCollectively these standards define the basis for Electronic Charting, and have been approved by the IMO.

DNC HThe NATO DGIWG has also defined an exchange standard called DIGEST for geographic information in a broader military context. HThere are many DIGEST products. HOne product is the Digital Nautical Chart. Unfortunately the S-57 ENC and the DIGEST based DNC are not directly compatible.

Harmonization HBoth DGIWG and IHO have worked together for many years to try to align ENC and DNC. H A mapping from the S-57 Object Catalogue to the DIGEST Catalogue is now complete, and the data models and meta objects are aligned. HDIGEST is adding ARCs and Update in line with S-57. HThis allows for “dual fuel” implementations in ECDIS systems, and for dual production from the same source. HHowever, the two standards exhibit different characteristics that limit interoperability.

Abstract Model Standards HAnother standards organization of importance is the International Organization for Standardization Technical Committee on Geographic Information Geomatics TC211. HISO TC211 is developing a suite of abstract standards for all of GIS that will provide a framework for standards such as S-57 and DIGEST. HUsing the TC211 base standards will allow application area standards to concentrate on the information content.

Content Models HThe information content in a geographic information data set is the part of value. HThe content model represents the data that can be converted into many different formats.  As long as these formats are capable of carrying all of the content, then the essential information is carried.

The content model and components HDefining information in terms of a content models and components is preferable to defining complete exchange standards. H Every set of data, whether it is temporary, or persistent and standardized, has a content model. HThis content model can be expressed in terms of a modeling language, and basic components can be shared. HThis increases the commonality between systems, since systems can be developed to support many different content models.

ISO Developing Components HThe (ISO) is developing a suite of abstract standards and components form which to develop other common Geographic Information standards. HStandards such as S-57 and DIGEST will become TC211 profiles. HDGIWG has announced that DIGEST edition 3.0 will be at TC211 profile. HIHO has not gone as far yet, but has indicated that the direction is toward being a TC211 profile.

ISO TC211 Rules Rules for application schema Feature cataloguing methodology Quality evaluation procedures Positioning services Portrayal Encoding Services Components Spatial schema Temporal schema Spatial referencing by coordinates Spatial referencing by geographic identifiers Quality principles Metadata Schema for coverage geometry & functions Simple Feature Access - SQL Reports (and input to other Projects) Functional standards Imagery and gridded data Qualifications and certification of personnel Imagery and gridded data components Guidance Reference model Overview Conceptual schema language Terminology Conformance and testing Profiles

An S-57 Content Model HS-57 is a feature oriented boundary (vector) based data description. It currently defines: Han Object Catalogue including capture rules; Ha data model consisting of an application schema and spatial schema; Ha set of attributes data in the application schema which forms a list of information about the information (i.e., metadata). HThis is the S-57 content model. It is important in that it does not change. However, it can be described differently. HDescribing it in terms of the TC211 suite of standards will make it easier to use other commercial software to implement the content model.

An ISO compliant encapsulation HISO TC211 separates encapsulation from data content. HIt defines a general encapsulation standard ISO that describes the method of converting a content model or schema element into a general exchange structure and then converting that exchange structure into one of several possible encoding formats. HAn neutral XML encoding format is defined as the default encoding.

8211 obsolete HISO 8211 is now obsolete. H ISO JTC1 has considered dropping the standard, and the maintenance of the standard is not currently assigned to a sub-committee. The standard is retained as a "mature" standard as long as it is being used. HIHO TSMAD is considering developing an XML encoding, as an alternative for S-57 edition 4.0. (retaining the older approach for backward compatibility)

Portrayal HAn important aspect of the IHO work on electronic charting is the S52 Presentation Library. In IHO this is considered to be separate from S-57, but it is driven by S-57 objects. HA similar portrayal standard has been developed in TC211. It defines a generic object centered rule based presentation mechanism that is compatible with the IHO S-52 presentation library. In fact the work on the TC211 CD on Portrayal has been heavily influenced by the IHO work. HThe TC211 standard defines a general rule based presentation mechanism that fits in the TC211 model. In this context the IHO presentation library is a set of rules that would drive the ISO mechanism.

Update HISO TC211 has addressed the issue of update as part of its work on CD Encoding.  It has taken the IHO (Add, Modify, Delete) incremental update approach. HDGIWG is also now considering this approach.

ICE Data HThere currently is no standard for ICE chart data. The data is supplied in the format the customer wants.This is expedient in the short term, but inhibits the development of commercial systems and services. HICE chart data is of two types: HVector chart overlays, and HRaster satellite imagery.

Vector Overlay HThe vector based overlay of a hydrographic chart with ICE data can be accomplished with the addition of a few new objects and attributes to an S-57 data set. HThese objects and attributes were developed about 5 years ago through a series of ICE data workshops, but they were never added to S-57 (for several reasons). These will be discussed separately

An S-57 add-on HThe basic S-57 exchange standard can handle additional these additional objects, and it is likely that most ECDIS equipment could handle it with little or now change. HSome new S-52 presentation rules will be needed HOne barrier is that nobody wants to touch the S-57 document because it contains the IMO approved ENC product specification.

MIOs HIHO is also studying Maritime Information Objects as an add-on to S-57. HVector based ICE objects can be added as a new IHO specification (S-63) through thye MIO committee without touching the existing S-57 document. HA draft standard for trials could be developed very quickly. 4(I feel that this should be a recommendation of this workshop.)

Raster/Image Data HThere are a very large number of imagery standards for different uses (HDF, CEOS, ISPRS, DIGEST, BIIF, Geo-TIFF). HISO TC211 is developing a common content model and structure for coverage type data (allowing for different encodings) HIHO TSMAD has indicated that it will not develop its own Raster/Image standard, but use the TC211 work.

Linked Raster HBoth vector and raster data can be geo- referenced and co-presented. HRaster data can also be object linked. HTC211 is also supporting complex “coverages” such as sonar sounding data and satellite radar data.

ICE in ECDIS Standards ¬Vector based data that complements a S-57 ENC. ÔA new IHO (S-63?) as an add-on to existing ENC. ÔDraft based on previous work. ÔProceed to testing ­Linked Raster/Image data. ÔBased on TC211 “coverages” work (as per IHO) ÔInitially only geo-referenced images. sBoth to work together.

%For additional information contact: C.D. O’Brien, IDON Technologies Inc. 280 Metcalfe St. Suite 301 Ottawa, K2P 1R7 Additional Information