CHAPTER 3 - THE ACQUISITION OF SECONDARY DATA FOR A MARINE FISHERIES RESOURCE GIS

3.1 Introduction

All secondary data represents primary data which has been converted into a more accessible and processed form. The variety and sources of secondary data is huge, and Table 2.1 briefly indicated this. From the marine fisheries viewpoint, Table 3.1 is an attempt to show the types of data and data sets which may be available. Obviously this table is not exhaustive and it would be possible to have numerous sub-categories of each. All of these sources are held in hardcopy format and many of them are now available in digital or film form as well. Some of the data is clearly in mapped or graphical form, other is textual and the remainder may be tabular. We would caution readers that actual access to secondary data varies greatly from country to country, i.e. some countries such as the USA consider most data which has been collected by the government as being in the public domain, and there are few barriers to its access. Most other countries consider data as belonging to the agency that collected it, and access to it may be strictly controlled. As a result of the diversity of marine related data sets, there have been attempts at various levels to ensure the standardization and maintenance of data sets. Table 3.2 gives useful examples of some organizations responsible for collecting marine data.

* Subsequently renamed the IOC Technical Committee on International Oceanographic Data and Information Exchange (though retaining the same acronym).

There are several trends and problems which are in evidence regarding secondary data sources. A major trend is the exponential growth rate of many of the published information and data sources, e.g. especially academic and trade journals, topographic maps, conference proceedings and CD-ROMS. To help access this data, which traditionally has been sought in hardcopy abstracts and bibliographies, there have developed first microfiches and more recently CD-ROM databases and computer “on-line” networking facilities. The problem with obtaining secondary data via networking, is simply the sheer volume available and therefore the difficulty of finding exactly the data required. In section 3.4 this is examined in more detail. Searching for data is theoretically becoming easier with the “on-line” electronic search facilities in many of the larger libraries, universities, research facilities or government offices. These give instant access to the resources held within the institution or they provide references to particular subject areas which may be of interest. The problems associated with on-line facilities are that they are sometimes difficult or expensive to access and, once having found a quoted reference or abstract, it can take some time to obtain a full copy. There is also a trend towards publication in the English language and a move towards more subject specialisation.

In the main secondary data which may be relevant to GIS's can best be examined under three headings (i) mapped, (ii) tabular and (iii) digital data.

3.2 Secondary Maps and Their Sources

Existing mapped information has undoubtedly been the major source of data for most GIS initiatives. This obviously results from the fact that the very essence of GIS is concerned with spatial allocation considerations, the subject of which best lends itself to various forms of mapping. Space precludes any consideration of the importance or methodology of mapping per se-interested readers should consult Muehrcke (1986), Butler et al (1987), Monmonier (1993) or Robinson et al (1995). Here we shall simply describe the main types of maps available, and potentially useful for a marine fishery resources GIS, and then suggest some of the sources for obtaining these. Whilst our discussion will be in terms of hardcopy maps, it is essential to mention that a large proportion of mapping being produced by government agencies in developed countries may also be acquired in digital format. Obviously this is extremely useful from the GIS viewpoint, and so digital data sources are examined in section 3.4.3. For convenience we can categorise maps as being of three main types-hydrographic, topographic and thematic.

3.2.1 Hydrographic Maps and Charts

Most countries having direct access to a sea or ocean coastline produce hydrographic maps. These are maps which typically show the coastline, bathymetry, isolated depth soundings, obstacles, navigation buoys and lights and other relevant navigational information. They are usually produced by some maritime authority or the official government mapping agency. The scale of the maps varies from 1:50 000 upwards to 1:10 000 000, though for port areas more detailed sheets are available. All standards for world sea mapping are regulated by the International Hydrographic Organisation.

As an example, the Hydrographic Office (HO) in Britain publishes 3 300 sheets of the world- wide Admiralty Chart series. These are the authorative source of navigation information for many countries which might not produce their own maps. These maps are kept constantly up-to- date. The HO also produce many other map series which might form a valid input to a GIS, such as tidal charts and the 74 volumes of the “Sailing Directions” which describes all the world's coastlines. HO maps are available from a network of chart agents located in most major ports.

Another series of hydrographic charts which are specifically compiled for use by fishermen are the Kingfisher Charts. These cover all British waters, plus the North Sea, Irish waters and some French and Icelandic waters. These maps give detailed depth information plus the position of wrecks, cables, pipelines, wellheads and other obstructions. They also show seabottom types. Obviously they are particularly useful in planning bottom trawls. They may be obtained from the company headquarters in England plus many overseas agents. Sea bed sediments and bathymetry can also be obtained from the British Geological Survey 1:250 000 Sheets covering 1 degree of latitude x 1 degree of longitude for all British coastal waters.

3.2.2 Topographic Maps

These are the typical product from most national mapping agencies. They aim to portray and identify important features of the earth using levels of accuracy which are consistent with the scale of the map. They are usually produced in a series which covers a whole country. Topographic mapping will be by different scales which may be classified as follows:

All topographic maps have clearly defined keys, scales, direction indicators, a grid/co-ordinate system and many will be in colour. The individual features shown on maps will be a function of the map scale.

The world coverage by topographic mapping varies considerably from region to region and it is impossible to give precise details on this since in many countries topographic maps are confidential at certain scales whilst in some countries the actual quality of mapping is so poor, or the content is so dated, that the map may not be worth having, certainly for GIS purposes. Generally map availability is relative to a country's wealth or degree of development. Thus in Europe, North America and Australia, mapping at a scale of 1:250 000 or smaller is complete, and in most areas maps at a scale of 1:50 000 are available. In most parts of Africa, Asia or South and Central America detailed mapping (1:50 000 or larger) may only be available for urban areas; indeed Butler et al (1987) estimated that perhaps 42% of the world is mapped at this scale. There is no doubt that RS capability is allowing the rate of world topographic map coverage to speed up, but there is unlikely to be total coverage at a scale larger than 1:100 000 by the end of this century.

In acquiring topographic maps as a data source for GIS, the user should be aware of some potential problems. Many countries cannot afford expensive revisions so many surveys may be at least twenty five years old. Mailing (1989) has highlighted the general problem of inaccuracy, i.e. when comparing an RS image with a topographic map for the same area, and Parry and Perkins (1987) outline those areas where maps may be impossible to acquire. Every country will have its own spatial inventory processes, preferences and standards and the interested map user will need to find out these to his or her own satisfaction. Before acquiring topographic hard-copy maps for GIS purposes, the GIS user should consult the mapping agencies to ascertain whether the maps are available in digital format, and what date the most recent editions were published.

3.2.3 Thematic Maps

As maps have become increasingly complex, then sub-sets of the original information have been more frequently displayed. Since these maps invariably concentrate upon one topic they have become known as thematic maps. There would be an almost limitless number of thematic maps because the themes themselves are endless, and in view of the fact that there are far more scale variations among thematic maps than with topographic maps. Thematic maps frequently use topographic maps as their outline source and in fact much of the basic map detail might be retained. Figure 3.1 shows a typical thematic marine related map. Many thematic maps may abandon some of the basic principles of topographic accuracy in order to highlight some specific theme. So for instance, in a typical route map, spatial accuracy will often give way so as to produce a straight line along which places (or other features) are placed in their correct order with distances between each being written in.

Figure 3.1 Example of a Marine Thematic Map Showing the Distribution of Manatees and Their Habitat in Southern Florida, USA

Undoubtedly there is a move towards the publication of more and more thematic maps. This has evolved out the growing recognition of the usefulness of maps, the fact that an increasing number of specialised publications include maps amongst their illustrations, that there is increasing spatial planning activities at all scales and to the fact that computer graphics (and GIS) has allowed for an explosion of digitally produced thematic maps. Thematic maps may therefore be produced in a huge variety of scales, they may very considerably in there physical size and they may be found in leaflets, books, atlases, promotional material or in a variety of specialist publications. Although there is no universally accepted classification of thematic maps, Figure 3.2 shows and describes some of the major types which are easily identifiable, i.e. by method of cartographic representation.

	Characteristics
	These show non-quantitative surface distributions of any feature, e.g. a map showing sea bed variations would show areas of mud, of rock, of sand, etc. These maps can have a huge range of classes with a different colour or range of shading for each.
	These are quantitative maps which depict average values of some feature per unit of area, e.g. a population density map. A maximum of about seven classes is used and shading is from dark (high density) to light (low density).
	Isopleths are lines which join places having an equal value. So a bathymetric map is an isopleth map since it shows lines which join places having equal depth below sea level. Other common isopleths include isotherms, temperatures), isobars (air pressure), isohalines (salinity), though there are many other possibilities.
	Maps that show point distributions are punctiformal. Thus the location of any individual objects can clearly be mapped with the representation appearing as simple dots, or as some pictorial symbol or shape. Obviously, what can be mapped as a dot on a small scale map might not be punctiformal on a large scale map.
	Many features show linear distributions, e.g. rivers, fences, roads, railways, sea routes, etc. Most linear maps simply show the lines followed by a feature, but they can also be volumetric by making the width of the line proportional to say the volume of traffic using a particular routeway.

Figure 3.2 Some of the Major Types of Thematic Mapping

The ease of actually acquiring any of the hardcopy topographic or thematic maps will vary tremendously, largely as a function of where you live and what you are seeking. Nearly all countries have their own national mapping agencies who supply maps to a range of retailers. These retailers typically keep a range of the more popular maps in stock, usually having maps at several scales of the local area, and they will order more specialised maps to customer requirements. It is now becoming possible in some countries to get larger scale local plans digitally printed at the map retail agency, on a “while you wait” basis, covering the exact aerial extent preferred. Many public libraries will keep reference copies of most local maps. There are a number of major commercial mapping companies who publish high quality maps and atlases, e.g. Bartholomews, Geographica, Hallwag, Michelin, Oxford University Press, Philip's and Rand McNally. These companies usually supply detailed catalogues. Many local and national government departments produce a range of thematic maps which are often very detailed, though of variable dates. In some countries there are national map libraries, such as British Library in London which has a collection of more than 1.5 million maps, or there are specialist map shops in the major cities. A visit to any of these sources frequently results in the potential user being pointed in the right direction!

3.3 Tabular Data Sources

Here we shall be briefly concerned with that hardcopy data, which exists in numerous tabular forms, usually consisting of a mixture of aggregated numeric and textual data which has been collected and presented in some logical and cohesive format to satisfy any one of a number of requirements. The presentation formats may vary enormously, from simple one off tables to huge volumes of collated forms. Most tabular data is the type of information which is increasingly being kept on computer databases.

In the author's experience gathering tabular data can be a very frustrating task. Thus, although in most countries there are vast amounts of data, actually acquiring that which is useful or desirable is fraught with problems. So, for instance, much of the data will be classified as confidential, or it can only be released to the general public either after a long time period or with the given permission of certain levels of authority. Many of the records are incomplete or outdated or of dubious levels of accuracy. Much of it may be stored in distant archives or, although it should exist, it cannot be located. Many organisations are even uncertain of the data that they might hold. Also, to be of any value to a GIS, there must be some form of geo- referencing. Frequently this is missing or the levels of dis-aggregation are so poor that it is valueless for any spatially based exercises. So the collection of tabular data will usually involve a large amount of patience and a good measure of discrimination as to its real value. We suggest an approach to collection which encapsulates diligent and polite persistence, though in most cases we envisage that existing tabular data should be ignored, and the user would be advised either to seek existing digital databases and/or to set up purposefully designed data collecting systems. Table 3.3 attempts to outline some types of authorities who may be able to provide tabular data useful to a marine fishery resources GIS.

Table3.3 Some Potential Holders of Marine Oriented Tabular Data

3.4 Digital Data Sources

As we showed in sections 2.3.3 and 2.3.4, a large amount of data is now being collected that is put directly into a digital format, i.e. so that it is potentially of immediate use in a GIS, and vast amounts of data has already been converted to digital formats. It is important to mention initially, that the utility of much of this data varies depending on the data models, structures and standards that have been applied. Before using acquired digital data it is as well to check on its utility and reliability first. Theoretically, this should be possible to do via the meta database kept by the digital data source provider (see section 4.4). Since the range of digital data is so vast we can only illustrate prospective lines of enquiry which show where some of it may be obtained.

3.4.1 Networking

Although it is obvious that any GIS is likely to require huge amounts of digital data, possibly of many different types and from many different sources, and there has long been the recognition that the thousands of existing databases could prove to be of value to many GIS users, until recently there have been few moves to initiate cataloguing systems which can expedite the locating of suitable databases. So the chances of ever finding out whether desired databases were already in existence has largely relied on chance or word of mouth. However, given the rapid growth in all aspects of computer information technology, and especially in light of the capacity of the latest technology to handle vast amounts of data, and of the recognition that data gathering costs will now greatly exceed likely systems costs, specialised data information networks are now appearing. Most of these are presently confined to a relatively few developed countries, but databases are rapidly becoming accessible world wide through the growth in electronic networking. In this section we will describe the sorts of databases and types of services which might be available, by giving some case studies within some countries who very actively operate database networking facilities. For readers wishing to find out more on electronic databases available, the charging or pricing systems, or on networking generally we recommend Kehoe (1992), Krol (1992), Newton, et al (1992), Rose (1993), Dern (1993), Hahn and Stout (1994) and Bostock (1994).

A “network” here is essentially when two or more computers are linked together to facilitate data or information exchanges. Although computers can be linked within a building on a Local Area Network (LAN), most “networking” is carried out over Wide Area Networks (WAN's) using either existing telephone lines or dedicated data lines. Chapter 5 gives more details on these networks. Both local and wide area networks may have access (or “gateways”) to considerable volumes of data which are not held within a corporation. Thus in many countries (and internationally) a number of electronic networks have been established which specifically allow for instant communications and data transfer between computer users in distant locations. Some networks operate within a country, e.g. JANET (Joint Academic NETwork in the UK), though they all have international access through the International Packet Switch Stream network. On the international scale the dominant network is the Internet. This is in fact a conglomeration of computer communication networks that manages, despite its complexity, to present a uniform face to its community. The Internet has its backbone in the USA. It was originally intended for the use of research or academic personnel, but it now has connections to government agencies, private corporations, libraries etc, plus the general public. Although local connection charges may be made, the actual usage time on the network is free. The total number of Internet users worldwide was about 25 million in 1994, with growth having doubled over each of the previous two years.

To gain access to the network, users or institutions require a leased (or dial-up) telephone line, a MOdulator/DEModulator (MODEM) and a computer with an appropriate communication interface (Figure 3.3. Users must also have their own identification code. It can be seen that a modem is the essential piece of hardware for networking and thus for obtaining access to remote databases. Modems are basically devices which allow for the connection between computers located in separate places. They may be either of a fixed, permanent type (direct connect modems), or an acoustic coupler modem which allows for an ordinary telephone handset to be placed in the modem so that data transmission can occur when required.

For networking, and therefore electronic data transference, to expand there are a number of technical obstacles which are presently having to be faced and surmounted: (a) Standards. The growing “global information technology industry” will be totally dependent for its long term future on internationally agreed standards for hard and software components and for data exchange systems.

Figure 3.3 Communications Between User and Database via a MODEM and Network (from Maguire, 1989)

Given that most of these obstacles are likely to be rapidly overcome, the practical use of networking is certain to grow exponentially. The primary use of much networking to date has been the transference of personal messages via electronic mail (E-Mail), or the pooling of information among persons who join up to specialist “lists”, e.g. there are a number of special GIS lists such as EDGIS-L, ESRI-L, COASTGIS-L, CONGIS-L, etc, all of which operate on a world wide basis and through which the user can seek and share information. There are also a number of electronic journals beginning to be set up on the network as a rapid means of spreading the results of academic research. The network is also proving very useful for the almost instantaneous transmission of data files. And it is not only data or information which can be transmitted in this way. There is already evidence that the transmission of the final GIS raster or vector maps will be possible via networking, i.e. now that methods have been found which allow for the compression of the huge amounts of data involved (Knott and Shiers, 1994). At its present stage of development, perhaps the major problem with the Internet is the fact that there is a vast collection of data to be found, but it may be extremely difficult to find what you are looking for!

3.4.1.1 An Example of Some Canadian Marine Networks

Most of the information in this section is condensed from Butler and LeBlanc (1990) plus personal communications from Butler (1994). This particular example has been selected because the eastern seaboard of Canada appears to be the most advanced area in terms of the implementation of the networking of marine databases. Having the world's longest coastline and 16% of the world's surface area of fresh water, Canada has a long tradition of utilising aquatic resources. However, the eastern seaboard especially is subject to a wide variety of pressures which threaten the development and management of its resources. These pressures come from various agricultural and forestry activities, community and industrial relationships, shipping, dredging, hydro-carbon and mineral extraction, marine resource depletion, plus more broad scale phenomena such as global warming, sea level rising, air pollution and shoreline erosion. To help alleviate the harm caused by some of these pressures, a number of governmental agencies and private organisations have been set up, and there has been a strong recognition that the accumulation and dissemination of data will prove to be a key constituent to success. Having both a comprehensive communications network and a large number of computer literate data users, then the networking of data and information is already proving to be a valuable move forwards, affecting many aspects eastern seaboard community life.

We now briefly describe some of the developments in the major information and data transfer systems which have been, and are still, emerging here. The various networks and information systems all fill slightly different roles and operate at very differing scales, though in many cases there will be overlaps in the services. An umbrella organisation, The Atlantic Coastal Zone Information Steering Committee (ACZISC), now acts as a focus for the development of the information infrastructure, and in 1992 the Committee produced an “Atlantic Coastal Zone Database Directory” which is an aid to promoting the various networks. The directory describes 408 databases which are relevant to Atlantic Canada. Figure 3.4 shows the overall infrastructure of the Atlantic Coastal Zone Information System. The following network list will not describe any of the foreign or international networks which would, of course, also be available within Canada.

(i)   Marine Environmental Data Service (MEDS). This was established in 1973 by the Dept. of Fisheries and Oceans (DFO) as a national service for the management and care of oceanographic data, which had been acquired by various means and which applied to Canadian waters. Data is provided by MEDS to the marine community generally, and it includes mainly oceanographic station data, tide and water level data, wave data, drifter data and current meter data. As well as providing raw data MEDS will add value to their data in any user defined way, carry out digitising, advise on where data not held by them may be obtained, acquire data from other national systems, etc. Services provided by MEDS are generally free for small jobs and costs are recovered for larger data provision.

Figure 3.4 The Overall Infrastructure of the Atlantic Coastal Zone Information Management System

(ii)  Ocean Information System (DFONET). This system is being set up by the DFO, but it is intended to be much more wide ranging than MEDS. Figure 3.5 schematically illustrates how DFONET functions. In the middle is the network which can be linked locally, nationally or internationally and it can expedite E-mail or data gathering functions. The upper portion of Figure 3.5 shows the information and services available. Most are self explanatory, though the “Distributed Inventory” functions act as a meta database. Note that data flows are two way, i.e. the network is obviously not just considered as a data gathering function. The “Modelling Nodes, Data Generation” ultimately require super-computers to aggregate data and prepare and run models. The lower portion of Figure 3.5 illustrates the anticipated users of the network. Here, “Broadcast Users” represent, for example, the marine weather forecasting community and “OGD” is other government departments. The Ocean Information System functions under four sub-systems:

(i)  data collection and distribution;

(ii) product development and distribution;

(iii) product evaluation and

(iv) research and development.

There are several major ways in which the system is being further developed including the investigation of ways of speeding up communication linkages, the incorporation of ERS-1 satellite data, the development of expert systems (including artificial intelligence), the further development of products and services and they are looking into future super-computing requirements.

Figure 3.5 Schematic Representation of the DFO's Ocean Information System (DFONET)

(iii) Gulf Geographic Information System (G-GIS). This has superceded a previous system known as IFISH/G-GIS. This system integrates a number of databases on fish habitats, the environment and man's activities that impact on fish, fishing and fish habitats in the Gulf of St Lawrence area. It is operated by the DFO at Moncton, New Brunswick, it uses a CARIS GIS and the system is presently being expanded.

(iv) Coastal Ocean Water Level Information System (COWLIS). This system is being developed privately in response to marine shipping, safety and resource management requirements and it integrates the real time telemetering of modern tide gauges into the data network. A central system gathers the tidal data from numerous gauges via modems, and the user can gain access to this data via special COWLIS “Tideview” software operating on a PC.

(v) Foreign Fishery Information System (FFIS). The DFO is responsible for the management of domestic and foreign fishing activities within Canada's 200 mile EEZ. Thus it must plan and supervise surveillance activities, patrol fish and habitat areas, license foreign vessels, inspect fishing activities and monitor vessel movements. To help in this work, the DFO has a networked database system called FLASH which is housed on a mainframe computer at its Toronto headquarters. Data is input daily and the service provides an automatic mechanism for recording information regarding licenses, quotas, catch and effort statistics and the surveillance of foreign vessels.

(vi) Electronic Chart Display and Information System (ECDIS). For several years the International Maritime Organisation and the International Hydrographic Organisation have been developing an electronic chart system, comparable to conventional paper charts, which is called ECDIS (see Huet, 1992 or Smith, 1990 for a summary). Working with satellite GPS and other information systems, ECDIS can show the position, course and track of marine traffic on a computer screen. Figure 3.6 shows a model of the proposed system - ENC is electronic navigational chart, the system is SENC, ECDB is the electronic chart data base and ENCD is the electronic navigational chart data. Trials of the system have been taking place involving Canada and eight European countries plus the Norwegian Hydrographic service vessel M/V “Lance” and, providing that certain conditions are met, access to huge volumes of hydrographic data should soon be available via the network. At a local level the Canadian Hydrographic Service is investigating a complementary electronic chart data base system called POD (Print On Demand).

(vii) Atmospheric Environment Service (AES). This government run service consists of supplying data on a series of inter-related climatic subjects, e.g. marine and coastal meteorological data, time series of extreme climatic data. There are seven systems which currently control each data area, i.e. as well as raw data, the service provides such things as basic statistical summaries, contingency tables for combined probabilities, contour analysis of selected parameters and likely return periods of extreme events. The service can be accessed by users having a special account and the appropriate user manual.

(viii) Similar to the above, but operated by a private company, is the MacLaren Plansearch Weather Information Network System (WINS). For its functionality, WINS relies upon any number of PC's networked to the company's main DEC MicroVax computer. Any of several different weather related data streams can be transmitted via Telesat Canada's Anikom 100 service. Information is received by the client's own satellite dish which may be sited at any location.

Figure 3.6 Schematic Model of the Electronic Chart Distribution System (ECDIS)

(ix) Ice Data Integration and Analysis System (IDIAS). A private company, MacDonald Dettwiler and Associates, are currently building for the Ice Centre of Environment, Canada, a data system which geo-references, processes and displays an assortment of ice related data. This is mostly with the intention of monitoring sea ice for fishing, hydrocarbon exploitation and navigation interests. Raw data for the system comes from either reconnaissance aircraft carrying various RADAR systems or from NOAA, Landsat and ERS-1 satellite imagery. A range of data products will be available to the networked user. The system's operational and data flow systems are shown in Figure 3.7.

(x) Inland Waters, Coastal and Ocean Information Network (ICOIN). Very recently, this new network has become established on behalf of the DFO. It is based on a series of regional databases, e.g. with an Atlantic ICOIN being set up at the Champlain Institute in Fredericton, New Brunswick. “ICOIN will provide a new information infrastructure, a network of distributed geo-referenced data bases to support environmentally sound sustainable development and management of Canada's oceans and freshwater areas.” (Butler and LeBlanc, 1990). The authors state that the idea behind this new network is to have one fully comprehensive data source, with the implication that the current situation in gaining data access is too fragmented in terms of subject areas, accessing rights, standards, quality, etc.

Figure 3.7 Schematic Diagrams Showing Data Flow (A) and Operational Configuration (B) of the Ice Data Integration and Analysis System (IDIAS)

(xi) Networked Distributed Environmental Information System Project. This project is a proposal to design and build a fully operational network of GIS stations to enable a variety of users to share in a marine environment information system. In other words the electronic mail network system will be linked to distributed GIS's to allow for GIS functionality over the network.

3.4.1.2 Some Other On-Line Databases

Most of the information in this section is taken (with permission) from Bostock (1994). This, together with Butler and LeBlanc (1990), is one of the few hard-copy sources which gives specific references to on-line database sources on aquatic sciences. Bostock is useful in that it provides a clear and simple overview on networking generally, and in the “Guide to Resources” chapter, the author not only outlines factual databases but also gives details on electronic bulletin boards, mail lists and newsgroups, bibliographic databases, library catalogues and various other document sources. The Appendices contain a comprehensive listing of database services, networking groups and organisations plus numerous references on networking. We have selected a range of factual on-line databases which could provide useful data for input to a marine fisheries GIS.

(i)   CHRONOS FISH. This is a database of fisheries statistics providing annual catch data for more than 1000 varieties of fish per statistical zone for every country in the world, monthly data on landings at European Community ports, statistics on the European fishery fleet, summary data on foreign trade and on supply balance for fish products. Information starts in 1988 and is available in French, German and English. Access is via the networking system WEFA CEIS.

(ii) NEEDS-AG. This is a time series database, commencing in 1960, of Japanese agricultural, forestry and fishery statistics. It is available in Japanese and English via NEEDS-NET.

(iii) MEDIFAUNE. This is a textual and numeric database on 6000 Mediterranean marine animals, their distribution, ecology, life history, biology, etc. It is produced by the University of Nice and is available through the Centre Interuniversitaire de Calcul de Nice et Toulon. Its records start in 1758 and they include some information on the markets for marine species.

(iv) OCEANIC. This is the University of Delaware Oceanography Service. It contains on-line oceanographic data including the World Oceanic Circulation Experiment (WOCE), research ship schedules and a Who's Who of E-Mail addresses in ocean science. Access is via Telnet.

(v) USNO. The U.S. Naval Observatory Automated Data Service provides a database on navigational information, satellite positioning, astronomical data and software utilities. Access is again via Telnet.

(vi) ODES. The Ocean Data Evaluation System has been developed by the US Environmental Protection Agency. It contains over two million records and data from a range of EPA programmes and the system resides on a mainframe at the EPA National Computer Center in North Carolina.

3.4.2 Remotely Sensed Data Sources

Satellite derived RS data is usually available at a variety of pre-processed levels. According to Stuttard (1992) this causes problems for GIS users in that the majority of data supplied is typically “level 1” data which consists of raw reflectance values which have been geo- referenced. For GIS use it is desirable that processing to “level 4” (or beyond) has been undertaken, i.e. the image has been corrected for distortions (see Section 4.6) and various other pre-processing work has been undertaken. Even then many GIS users will require details on actual land use (or the meaning of the reflectance variations), as shown by the pixel values, and this is not usually available. However, with this need to both make RS imagery more user friendly and to ensure that costs can better be covered via adding value to the products, some of the major RS data suppliers are now supplying imagery to suit customer demands, e.g. Satellitbild, SPOT Image and the National Remote Sensing Centre (NRSC) in the UK can supply geometric and radiometrically adjusted image data on various storage media, and most major suppliers can offer products which have been pre-processed to various customer defined levels and which are centered on customer chosen spatial centroids. One example is the NRSC and Ordnance Survey's seamless national RS dataset, which is offered in various formats and scales, and which has been ortho-corrected such that it can easily be integrated into many GIS's, perhaps to form a background to vector displays. A promising future growth area for remote sensing is in the supply of backdrop imagery, either for use in specialist GIS generated maps or for topographic mapping, and many new companies are now marketing RS image processing software which is usable by non RS specialists.

A major problem with acquiring satellite RS data is knowing exactly what is available from the huge quantity of Earth observation data which is now being received, and which has been collected in the past. To help with this problem new image data searching facilities are about to come on line. For instance, the European Space Agency (ESA), in conjunction with the EC's Centre for Earth Observation (CEO), are developing a user interface terminal to provide a single point of access to multiple inventories of satellite imagery. This follows the development of a robust cataloguing model, under the auspices of the Committee on Earth Observing Satellites, which lays down a rigorous, structured approach to data entry into catalogues. The catalogues will be able to be queried so as to answer such questions as - “List all the cloud free images available for SPOT-2 data of the Red Sea taken during 1992”. This system should be fully functional by 1998. A similar system is operating in the USA. Here the various offices of the National Cartographic Information Center (NCIC) can help individuals locate images via computer database search facilities. Following this same conceptual basis, plans have been put forward for the establishing of a “Marine Remote Sensing Information System” (MARSIS) (Barale, 1991).

Imagery may be obtained from a range of local, national and international sources, some who specialise in one satellite system whilst others may provide for all systems plus a range of other connected services. Figure 3.8 gives an example of the type of information which would need to be supplied in order to obtain RS imagery, with this particular form being applicable to registered ERS-1 users. Some examples include:

(a)  EOSAT - this is the USA distributor of Landsat Multispectral Scanner (MSS) and Thematic Mapper (TM) data, and a world distributer of IRS 1A and 1B data.

(b)  Eurimage - they are the main European distributor for Landsat, ERS and other satellite data and they operate through 35 local distributors in Europe, North Africa and the Middle East.

(c)  Remote Sensing Technology Centre (RESTEC) in Tokyo distributes MOS-1 data in Asia.

(d)  SPOT Image in France prepare and distribute a wide range of SPOT imagery through a worldwide chain of distributors.

(e)  The European Space Agency (ESA) has a GENIUS programme to process, archive and distribute imagery, mainly using computer networking facilities. They handle data for several satellite systems. ESA have a chain of European distributors.

(f)  The NPA Group - they offer all imagery plus image processing equipment and expertise and they are specialists in Russian RS data.

(g)  When the one metre resolution imagery becomes available in 1996 it will be marketed by a new US company called Eyeglass.

(h)  The National Remote Sensing Centre Ltd (NRSC) are the main UK distributor for all RS products.

(i)  The National Aerospace Laboratory (NLR) are the main Dutch RS distributors.

(j)  Worldmap is a new consortium formed between a western company (Jebco) and two Russian remote sensing agencies, with the aim of processing and distributing both new imagery and that from the Russian archives.

(k)  In the USA, the U.S. Geological Survey (USGS) produces and distributes RS data sets on a world wide coverage from both Landsat and AVHRR sources, and prices for scenes which are more than two years old reflect only the cost of reproduction.

Most developed countries now have at least one major distributing company plus often a number of private RS distributing points. Many of the suppliers also have contracts with various Russian agencies to secure their data. Much of this is in the form of high resolution (down to 2 metres) black and white photographic images though a vast amount of other digital data is also available. There are also emerging specialist companies who will provide satellite derived information which is specifically oriented towards the fisheries industry, e.g. hardcopy data on sea surface temperatures and ocean fronts. Since this information is in mapped format, it could usefully form the basis from which scanned maps could be derived (see section 4.5.2).

Typical costs for satellite imagery vary according the source, scene size, the degree of pre- processing, etc. Table 3.4 gives an indication of prices for a small sample of the total imagery product range. However, since there are now so many companies supplying data, there is plenty of pricing competition and it is often possible to buy older imagery, or bulk purchases of several images, at much reduced prices. Some satellite data is available in near real time, e.g. for a premium price, processing and delivery of ERS-1 SAR imagery can be obtained in 30 minutes, and SPOT charges an extra US$2000 per image for archive scenes provided within 24 hours. Two useful sources of information which specifically relate to RS and the marine environment are Commission of the European Communities (1991) and UNESCO (1992).

Figure 3.8 Example of a Satellite Imagery Product Order Form for ERS-1 Output

Table3.4 Examples of 1994 Prices for Some Remote Sensing Digital and Photographic Products

3.4.3 Other Digital Data Sources

In this section we are considering the acquisition of a miscellany of digital data which may be available, usually on floppy disk or in CD-ROM format. Since the range of data could be virtually infinite, we can only list a sample of the types of product which are on offer. Although illustrations are drawn mainly from Europe and North America, in many cases there may be similar source institutions in other areas or the institutions mentioned have data for a wide range of marine locations. It is likely that many of the sources mentioned will soon release their data via computer networking systems. Table 3.5 shows typical digital mapping data available (plus prices) for a range of European information. Some of the GIS Trade Directories provide lists of digital data providers (see Section 8.3), and there are a number of general database directories, e.g. ACCIS (1990) and Nolan (1995). Before purchasing any of the digital data described in this section, the user should check its format, structure, accuracy, geographic area covered, date and its price.

Table3.5 Availability and Price (1995) of Selected Digital Data for Europe

(a)  The UK Ordnance Survey is now making available, initially on a trial basis, a number of coastal zone maps in digital format (see section 9.6).

(b)  The UK Department of the Environment produces a “North Sea Research Database” which is an integrated, PC-based system providing information on individuals, organisations and projects concerned with the North Sea.

(c)  The British Oceanographic Data Centre (BODC) maintains a national oceanographic database which provides a broad range of data to research scientists, industry and to local and central government. It has also produced a UK Digital Marine Atlas (UKDMAP) (see section 9.3).

(d)  As mentioned in section 3.2, digital hydrological charts are now becoming available. As well as obtaining these via networking, Wardle (1992) reports that these will be available on disk either as integrated parts of complete navigation software packages, or as separate digital maps for specific areas. Kingfisher Charts (see section 3.2.1) are now producing, in conjunction with the French marine research organisation IFREMER, a database called the European Seabed Information Service (ESIS). This will map all navigation and sea bed hazards in EC waters (Knox and Lalwani, 1994).

(e)  The US Defense Mapping Agency has produced a digital data file known as the World Vector Shoreline (WVS). It is at a nominal scale of 1:250 000, contains shorelines, international boundaries and country names and is in a format suitable for integration into most GIS packages via magnetic tape or CD-ROM (Soluri and Woodson, 1990). Various “spin-offs” or value added products have been produced from this work, e.g. MundoCart from Chadwyck Healey.

(f)  A similar product to the above is the Digital Chart of the World. This provides topological vector data at a base scale of 1:1 000 000 for the whole world, which makes it much more amenable to GIS uses (Danko, 1992). It comes on 4 CD's and contains about 1 700 Mb of data. It can be obtained from Chadwick Healey Ltd for about US$300.

(g)  The Public Works Department in the Netherlands initiated a North Sea “Marine Information Service” (MARIS) in 1985. This is a complete service which not only provides digital database information on disk (and on-line) but also carries out research, consultancy and gives guidance, etc. (van Eden, 1992).

(h)  The Eurostat GISCO project. Eurostat is a branch of the European Commission and is based in Luxembourg. The role of GISCO is to identify EC spatial data requirements and subsequently to acquire and maintain this data. A range of large databases are now available, many of which are marine related (Cubitt, 1992).

(i)  The GENIE (Global Environmental Network for Information Exchange) project has been established at Loughborough University in the UK, to provide a global environmental change data network.

(j)  The U.S. National Oceanic Data Center (NODC) can provide the following data sets on CD-ROM, magnetic tapes, diskettes or over Internet:

*   GEOSAT global wind/wave data, collected by satellite.

*   NODC taxonomic code data, i.e. a system of numeric codes used to represent the Linnean scientific names for organisms.

*   NOAA marine environmental buoy data, i.e. 14 CD-ROM's hold worldwide data collected from buoys on air temperature and pressure, wind speed and direction, wind gusting and sea surface temperature plus some data on waves.

*   NODC oceanographic station profile time series, i.e. these represent repetitive samples of parameters such as salinity, temperature, density, nutrients, etc, along ocean sections or at fixed stations for long time periods.

*   GEOSAT altimeter data which contains various geophysical parameters.

(k)  Barale (1991) reports the development of the Marine Remote Sensing Information System (MARSIS). This system is designed to make a far higher proportion of the RS marine data gathered available to potential users by delivering value-added data sets, both according to standard statistical procedures and to specific user requests. MARSIS data would originate from a number of regional centres which covered complete sea basins, e.g. the entire Mediterranean region.

(l)  The International Council for the Exploration of the Seas (ICES) has a large oceanographic digital data bank which is continually being updated. This covers a wide variety of parameters. Details regarding access to this data, the nature of the data and its format can be obtained from the Working Group on Marine Data Management at ICES headquarters at Palaegade 2–4, DK 1261, Copenhagen K, Denmark.

(m)  Floen et al (1993) reports the establishment of an integrated database for marine research at the Institute of Marine Research in Bergen, Norway. This is a centralised database containing all data gathered by the Institute. It mostly covers the Scandinavian areas and the data comes under the broad headings of “Marine Resources”, “Marine Environment” and “Aquaculture”.

(n)  The British Marine Fishes Database (BMFD) has been developed by the Marine Biological Association, Citadel Hill, Plymouth, UK, and it covers aspects relating to the biology and ecology of all marine fishes found in waters around the British Isles.

(o)  Froese (1993) reports on the current status of “FishBase”, which is a global database on over 8000 fish species, This has been developed by a consortium of international organisations including the EC, FAO and the International Center for Living Aquatic Resources Management (ICLARM).

(p)  For some parts of the world's oceanic areas, there are now databases of digital acoustic sounding data. Hittelman et al (1989), McLain et al (1991) and Danko, 1992) can provide further information on these.

(q)  The National Ocean Service (NOS) in the USA collects and distributes bathymetric data for all of the USA and territories, plus other islands in the Pacific and Atlantic.

(r)  The National Wetland Inventory (NWI) of the U.S. Fish and Wildlife Service provides information on wetland location and type, in digital format at a scale of 1:24 000 for most of coterminous USA. Wetlands are classified according to a Cowardin wetland classification scheme (Figure 3.9).

(s)  The FAO Fisheries Department has published a database which forms a global inventory of commercially important fish species (Coppola et al, 1994). The database is called SPECIESDAB, and it was created to offer quick and easy access to fisheries and biological information on over 3000 marine species.

Figure 3.9 Portion of the National Wetland Inventory Map in Florida, USA

(t)  UNESCO, in conjunction with the International Oceanic Commission (IOC), produces a “MEDI Catalogue” which is a catalogue of digital data holdings relating to marine environmental data (UNESCO, 1993).