Unfortunately, such normal implementation was
found difficult to accommodate any further
processes to delineate farmland. The farmland
delineation processes were developed in a previous
project. When each piece of farmland is delineated,
many homogeneous sub-fields (hereafter referred to
as D-field as delineated field based on topography,
such as aspect, slope, water flow direction, etc.) will
be created, along with many byproduct polygons
created by copy, buffer, intersect, union, and other
operations. This delineation process causes two
major problems for the normal E-R modeling
implementation described above. The first problem
is the fact that a piece of farmland, after the
delineation process, will be divided into multiple
pieces of land (D-fields). The second problem is the
fact that these D-fields will have a different set of
attributes from the original fannland