The Management of Oyster Culture Leases and Production
265
to extract banks is as follows. First of all, a query is made of the field
within the administrative data, after a logical join has been
performed with the parcel graphical file. All parcels of a given bank are highlighted.
Spatial merging of all parcels may then be performed which results in one (or several)
global polygon (s). Completion is achieved using the interactive graphical editing tools
of ArcView in order to end up with a polygon, which is labelled after the bank name.
All separate banks are then unioned to form a new shapefile.
More attributes may be appended to the bank entity. Apart from bank
committee data for instance, some biological data are available per bank : this is the
case of the biomass of wild stock for instance.
THE ADMINISTRATIVE DATA BASE
The
contains 32 items of information relevant to
each lease, i.e. its unique number, the owner number, the bank it belongs to, its
specific rearing activity, various dates (last movement, begin and end-dates) and so
forth. Another file is the
with various civil status data, which may
be linked to the previous one through the owner number.
These data are mostly for administrative use, although some of it may be of
interest for management purposes. Previous experience of a similar data base
construction and management had been gained by the authors with the development of
a GIS for pearl oyster culture in French Polynesia (Chenon, 1990).
This whole semantic data base is centrally maintained by
for the whole of France and it undergoes frequent updates. Therefore, in
order to maintain the data integrity, it is never modified in the project and is exploited
through logical joints with the lease graphical file.
265
to extract banks is as follows. First of all, a query is made of the field
within the administrative data, after a logical join has been
performed with the parcel graphical file. All parcels of a given bank are highlighted.
Spatial merging of all parcels may then be performed which results in one (or several)
global polygon (s). Completion is achieved using the interactive graphical editing tools
of ArcView in order to end up with a polygon, which is labelled after the bank name.
All separate banks are then unioned to form a new shapefile.
More attributes may be appended to the bank entity. Apart from bank
committee data for instance, some biological data are available per bank : this is the
case of the biomass of wild stock for instance.
THE ADMINISTRATIVE DATA BASE
The
contains 32 items of information relevant to
each lease, i.e. its unique number, the owner number, the bank it belongs to, its
specific rearing activity, various dates (last movement, begin and end-dates) and so
forth. Another file is the
with various civil status data, which may
be linked to the previous one through the owner number.
These data are mostly for administrative use, although some of it may be of
interest for management purposes. Previous experience of a similar data base
construction and management had been gained by the authors with the development of
a GIS for pearl oyster culture in French Polynesia (Chenon, 1990).
This whole semantic data base is centrally maintained by
for the whole of France and it undergoes frequent updates. Therefore, in
order to maintain the data integrity, it is never modified in the project and is exploited
through logical joints with the lease graphical file.