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Using GIS for Siting Artificial Reefs
project which relate directly to the data available for use in the study. Knowledge of the
source of the data, the method of data collection, capture, scale and sampling strategy
are all important if they are to be used in any analyses, modelling or simulation studies.
Without such information, it is very difficult to make use of the datasets, not in terms of
their practical usage, but in a legitimate way. Unfortunately information about the data
is not always recorded at the time of collection or forthcoming when multiple datasets
from multiple organisations are involved. Furthermore, there are currently few
requirements to collect spatial data to any UK standard, and no requirement to
document (metadata) the data, although bodies such as the AGI in the UK for example
have produced documents advocating the need to consider standards and data quality
(AGI, 1996). This means that without having such information to hand when using
'second and third-hand' data, it becomes very difficult to justify and to defend the use of
individual and combined datasets for an application, particularly where any analysis is
planned. In a practical sense the data can be used. However, there is considerable
potential for the generation of error. Without knowledge of the individual and
cumulative error contributed at each stage in an analysis it becomes very difficult for
end-users to make decisions based on the outcome of an analysis. In some cases the
error inherent in a dataset or generated through analysis may not be significant, and may
even be minimised. In other cases the output may contain sufficient error that could
affect the usefulness of the results, and even decisions made.
This chapter seeks to address some of the problems associated with these data
issues and problems, and to offer some practical solutions and guidance for the
practitioner. It is set in the context of the development of an environmental database for
the Moray Firth, North East Scotland, and more specifically the use of selected datasets
from the database for the proposed siting of an artificial reef. Using this example, the
chapter explores the problems associated with the use of both existing analog and digital
datasets as the basis for an environmental application, the problems of data acquisition,
quality, standards, and error, and how these can affect the operational use of the data in
GIS analyses. There is also the question of how one makes use of historical or archival
data e.g. in sediment movement studies, temporal changes where old datasets have to be
used out of necessity. The solution to such problems would appear to lie with improved
error assessment and reporting. The outcome of this chapter is an attempt to offer
guidance and solutions to researchers and applications specialists undertaking similar
studies. It suggests to what extent studies, such as the artificial reef example, can safely
make use of existing datasets without risking the problems associated with judgements
based on inadequate information, and generated or inherent error.
Artificial Reef Siting
To date it would appear that there is relatively little literature on the siting of artificial
reefs utilising GIS technology (see for example, Nakamuna, 1985; Bohnsack and
Sutherland, 1985; Matthews, 1986; Grove et al., 1991; Bruno et al., 1996; Herrington et
al., 1997; additional reading list of websites).
Using GIS for Siting Artificial Reefs
project which relate directly to the data available for use in the study. Knowledge of the
source of the data, the method of data collection, capture, scale and sampling strategy
are all important if they are to be used in any analyses, modelling or simulation studies.
Without such information, it is very difficult to make use of the datasets, not in terms of
their practical usage, but in a legitimate way. Unfortunately information about the data
is not always recorded at the time of collection or forthcoming when multiple datasets
from multiple organisations are involved. Furthermore, there are currently few
requirements to collect spatial data to any UK standard, and no requirement to
document (metadata) the data, although bodies such as the AGI in the UK for example
have produced documents advocating the need to consider standards and data quality
(AGI, 1996). This means that without having such information to hand when using
'second and third-hand' data, it becomes very difficult to justify and to defend the use of
individual and combined datasets for an application, particularly where any analysis is
planned. In a practical sense the data can be used. However, there is considerable
potential for the generation of error. Without knowledge of the individual and
cumulative error contributed at each stage in an analysis it becomes very difficult for
end-users to make decisions based on the outcome of an analysis. In some cases the
error inherent in a dataset or generated through analysis may not be significant, and may
even be minimised. In other cases the output may contain sufficient error that could
affect the usefulness of the results, and even decisions made.
This chapter seeks to address some of the problems associated with these data
issues and problems, and to offer some practical solutions and guidance for the
practitioner. It is set in the context of the development of an environmental database for
the Moray Firth, North East Scotland, and more specifically the use of selected datasets
from the database for the proposed siting of an artificial reef. Using this example, the
chapter explores the problems associated with the use of both existing analog and digital
datasets as the basis for an environmental application, the problems of data acquisition,
quality, standards, and error, and how these can affect the operational use of the data in
GIS analyses. There is also the question of how one makes use of historical or archival
data e.g. in sediment movement studies, temporal changes where old datasets have to be
used out of necessity. The solution to such problems would appear to lie with improved
error assessment and reporting. The outcome of this chapter is an attempt to offer
guidance and solutions to researchers and applications specialists undertaking similar
studies. It suggests to what extent studies, such as the artificial reef example, can safely
make use of existing datasets without risking the problems associated with judgements
based on inadequate information, and generated or inherent error.
Artificial Reef Siting
To date it would appear that there is relatively little literature on the siting of artificial
reefs utilising GIS technology (see for example, Nakamuna, 1985; Bohnsack and
Sutherland, 1985; Matthews, 1986; Grove et al., 1991; Bruno et al., 1996; Herrington et
al., 1997; additional reading list of websites).