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5 cadastral
ial objects
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' from the
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] stored, or
cadastral
Spatial
Description
Ownership/
Stewardship
Land use/
Uncertain resources
Economic
value/resources
Subject/
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Figure 1: Uncertainties in Cadastral object
In the practical situations, four basic principles,
namely the booking principle, the consent principle,
the principle of publicity, and the principle of speciality,
are followed in a land registration in order to avoid or
reduce uncertainties in the use of information.
In GIS system environment, Molenaar (1994) provides
three categories of statements in the handling
uncertainty aspects namely "the assignment of object
classes, the assignment of object attribute value, and
the assignment of spatial description to objects".
In cadastral world these statements are extremely
important to satisfy the users of PBIS. PBIS handles
not only legal cadastral parcels but also other spatial
objects like forest parcels, mining parcels, agricultural
farms, polluted areas and so on.
For example, to simplify data acquisition for taxation
purposes, cadastral objects are often classified as
urban, subrural and rural. Alternatively cadastral
parcels are classified according to present or permited
land use. First approach of classification does not
really serve to convince a tax payer, because his
piece of land may be situated in the fuzzy region.
Second approach does give some more concrete
ideas, but still give problems on the class values in the
valuation models. Thus appropriate classification
techniques are to be formulated to avoid any
ambiquity and confusion. Secondly the assignments
of attribute values are to be made using appropriate
data acquisition methods. Similarly in the case of land
consolidation or land reallocation, classification is
usually based on soil classes for valuation models.
These are only few examples of cadastral applications
in this paper with regards to the assignment of object
classes and attribute values.
Again the treatment on the spatial description has
been interestingly described by Molenaar (1994). This
could well be applied in the parcel objects which can
be fuzzy in the general boundary concept described
above.
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B3. Vienna 1996
Well formulated uncertainty information can be
documented in the deeds or titles of cadastral parcels.
5. CONCLUSIONS
The scope of this paper is to identify and underline
uncertainty issues in cadastral parcel boundary
concepts. The parcel boundary problems are
reviewed against the systems of land registration and
cadastral surveying. It then describes the uses of
parcels and consequences, if certainty is failed to
describe in the system environment. Since this is
initial phase of works, solutions presented seem
rather vague. However the approaches proposed for
handling uncertainty in parcel-based information
system seem promising.
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