In “stating our case” as to the relevance of both RS and GIS in making a contribution to the future success of both aquaculture and inland fisheries, it has become clear that, for a number of reasons, a brief conclusion is in order.
Firstly, the two subject areas (RS and GIS) have tended to be treated separately-we need to make it clear that the two areas have a degree of “mutuality”. Secondly, we are very conscious that certain barriers remain to an easy progression for the whole field of automated location analysis, and these are very worthy of a reminder. Thirdly, we feel it essential that a reinforcement is made of some of the more important practical systems adoption considerations. This is largely a result of the complexity of the subject matter and because of the rapid changes which are now taking place in both GIS and RS. This leads us to belive that a number of recommendations are in order.
When RS was first envisaged and activated in the 1960s and early 70s, there was a sense in which the object of the science was simply to obtain a “picture of a place”. The picture (image) might have a number of uses which were primarily concerned with identification, spatial proportion, aerial estimation, etc., and the number of usable images was limited by technical processing limitations, resolution problems and cloud cover. So the frontiers of RS had distinct limitations. The proliferation of GIS in the late 1970s, with its rapid ability to make use of RS images in a number of ways, and indeed its frequest fundamental need for imagery as a primary data source, plus the ability of RS to capture a wider range of images through the use of more varied sensors and an increased effectiveness in data extraction, has enabled the two disciplines to help each other and to broaden their raisen d'être. This mutual adoption was a highly necessary step if RS was to have an assured future. From the perspective of aquaculture and inland fisheries it is especially significant, since over the next decade we will be seeking to optimize fish production in a variety of locations, many of which are certain to be in areas which are remote or poorly mapped and for which the “real time” digitized data emanating from RS sensors will prove absolutely invaluable.
Though much of what we have previously explained on the more theoretical aspects of RS may have been useful with regard to process explanation and understanding, when the use of RS as a means of data acquisition is adopted then it is the acquisition procedures themselves which are of paramount importance. Specter (1989) has set out an excellent summary on the barriers to imagery acquisition, as faced by many developing countries, and he foresees considerable investments being made in money and expertise during the next decade with a view to improving the RS technology and data transfer systems to those areas. Significant reductions in the price of products would seem an essential pre-requisite for increased RS uptake, as would assistance in training and education in technology use.
With the advent of more “players” on the RS scene, then it is likely that increased competition will be beneficial in not only reducing prices but also in increasing the range and quality of images available. We recommend that potential RS users make every effort to “shop around” for suitable imagery. Cordell and Nolte (1988b) were able to verify that a huge quantity of RS data was available, i.e. from different satellites, for different times, at different resolutions and from various sources. With this data proliferation then, if sufficient or regular quantities of RS imagery are required, we suspect that tendering or contracts could be entered into so as to achieve cost advantages. And in searching for suitable imagery sources we would make a reminder that aircraft photographic sources could prove invaluable, especially in situations of micro-scale location analysis.
With regard to GIS we feel it important to re-inforce a number of separate practical issues and to make specific recommendations
Uses for the GIS. In section 6.7.1 we made it clear that considerable planning should be undertaken regarding the desired applications for the GIS. Relative to aquaculture and inland Fisheries this will mostly cover considerations of optimizing production locations, a task which will also encompass an analysis of production function variability. However, with imagination the utility of a GIS can be greatly enhanced. Examples of added investigations include:
As well as the potential uses identified it is important not to forget that changes in the scale at which GIS investigations are applied will allow for a variety of different potential uses.
How best could the GIS be implemented. Very great care needs to be given to the “levels” of implementation of the system. We would strongly recommend that a “top down” approach is used, i.e. rather that individual small departments setting up their own systems. With a “top down” approach there will be expertise and hardware available, sufficient resources for experimentation, the likelihood of some data archives and the backing of the management who are likely to be responsible for further GIS investments. Also future developments can expand in such a way that data structure, hardware, software, etc. is compatible, standardized and thus available for integration, and rapid expansion can occur, if necessary, both within and between departments.
The inter-disciplinary nature of the GIS team. We have spoken at length on the complex nature of all our subject matter, and we have noted (in section 6.7.6) the recommendations for having personnel from several disciplines in any team setting up a GIS. Here we would stress that, for the successful functioning of a GIS at a significant scale not only is it essential that a variety of experts in obvious fields are assembled but that these experts are able to have clear access to both the staff who make the GIS function (digitizers, programmers, etc.) and to a variety of other personnel such as data archivists, representatives of mapping houses, software and hardware companies and perhaps specialist consultants. Though these personnel might be expensive “luxuries” for the more remote fisheries offices, their accessibility should be well documented.
Knowledge of data sources. We have shown that a major problem for GIS in general is the accessibility to, and knowledge of, data sources. It seems that the barriers to instigating centralized and accessible digital data archives are almost insurmountable, i.e. regardless of country or theme. Because data acquisition is so expensive it behoves the GIS planner to investigate thoroughly requisite sources. We recommend that at least one member of any GIS team should be given specific responsibility for data acquisition. This member needs to be familiar with likely digital sources, with data distribution networks and with mapping and tabular sources both in his own country and preferably abroad.
The thoroughness of data capture and structure. The output from any GIS can only be a function of the data which has been input to the system, and it follows that weaknesses in the data will progressively replicate themselves in an exponential way with increasing use of the data. We strongly recommend that from the outset of GIS planning, considerable attention is given to the personnel and procedures necessary for ensuring that any data used is thoroughly reliable. Systems will need to be worked out to optimize the verification, correction and/or updating of data. Data accessing, digitizing and other capture procedures should be carefully considered and monitored, and thought must be given to the structuring of the data so as to ensure its efficient storage, integration potential as well as its ease of management.
Keeping abreast of developments. The reader cannot fail to have grasped that developments within the total sphere of GIS are taking place extremely rapidly. This pace of change will be manifest along three parallel continuums:
We must therefore emphasize the importance of keeping abreast of these developments. This may mean a commitment to a number of strategies including attending relevant courses and/or conferences, subscriptions to academic or trade journals, membership of professional associations, the acquisition of promotional literature and of being aware of what other companies, organizations or associations are doing.
To conclude this study we quote from Tomlinson (1989 - p.291–292) - “As space becomes more crowded, place becomes increasingly important. The public is expected to demand greater government involvement in such complex problems, thereby increasing both the responsibilities of government and the numbers of people addressing the issues. There will be more players with complex, interlocking spatial problems. There will be an increased demand for GIS capabilities at all levels of government, reflecting local, regional, national, multinational; and global concerns…” The application of RS and GIS to aquaculture and inland fisheries can be our contribution to meeting these needs.
