integration.
Decision Making
The decision making is frequently
presented with maps or statistic
products, derived from remote sensing
and GIS. In most situations,
appropriate information concerned to the
lineage of the thematic data layers and
accuracy associated to thematic and
geometry are not given. Besides this,
the decision making needs the total
precision estimate and the reliability
of the products used in the process,
although decision making is provided
with little or no acquaintance about the
potential error sources and no
information concerning to final accuracy
and reliability level.
There is a defined tendency between
many decision makers of always accept
products, maps and statistic reports as
truthful. Bor. the fact. of several
remote sensing and GIS products being
thematic products, there is an enormous
error potential in a decision making,
for overestimating the accuracy and the
thematic reliability level of the
products. It is necessary that the
remote sensing and GIS communities
instruct the administrators to better
understand the error sources associated
to the products.
Implementation
Decisions based on innaccurate data
and improper reliability level have a
great . probability of making incorrect
decisions. The obvious implications of
an incorrect decision are wrong actions
of resource administration, which can
mean serious consequences for the
resource itself, Causing its loss or
degradation, adverse impacts on a
particular ecosystem or its elements,
impacts on the human health, besides the
possibility of fines or other punitive
actions.
AS products derived from remote
sensing and GIS are raisingly being used
as decision basis for resources
management and as problems regulator,
there is a high potential for an
explosion of the number of litigations.
The biggest challenge for the remote
sensing and GIS community will be the
hability of properly portray and defend
the accuracy and reliability of products
used by administrators in the process
implementation.
CONCLUSION
It is necessary a considerable amount
of research and development to be made
before the errors associated to remote
sensing and GIS integration can be
properly quantified and expressed in
standard formats.
The objective of standard error
reports is to provide an evaluation
method of the adjustment of GIS products
derived from remote sensing for specific
applications and to facilitate the
comparison between several research
354
results.
The present procedures for remote
sensing errors evaluation were adapted
from statistic procedures which were not
Specifically developed for space data.
These techniques have been adapted and
have been reasonably good for small
areas, but their application for
regional or global grades is not
economically viable. For the fact : that
the existent techniques refer to the
global accuracy, the error Space
distribution is not evaluated. There
must be developed techniques to evaluate
the error space structure.
The philosophy and the
recommendations for the acquisition of
good field data to evaluate the maps
accuracy has not been well addressed.
Basic researchs must be developed on the
accuracy levels associated with
different ways of field verifying.
The classified satellite digital
images (representation pixel-by-pixel)
are easily filled in the matrix. format
but hardly converted into the vectorial
format.
Numerous rules have been done in
order to control the process of matrix
data conversion into vectorial, but the
effects on surface, size and accuracy of
the polygons, when compared to the
original matrix data, haven't been
studied with severity vet. ix is
critical to research the effects of the
conversion of remote sensing digital
data.
Additional information is required on
the characteristics of the location
errors in remote sensing and the
correlation between locations and
classification errors. It is necessary
more knowledge on the definition of
alternatives for remote sensing
Platforms and on how much the GPS
technology will contribute for the
accuracy of remote sensing data
location.
The final maps and statistical
products must be standardized to provide
information related to the accuracy and
reliability associated to the specific
data product.
REFERENCES
Aronoff, 3:3 1985. The minimum
accuracy value as an index of class-
ification accuracy. Photogrammetric
Engineering & Remote Sensing 51(1):99-
111.
Blakemore, M., 1984. Generalization
and error in spatial databases.
Cartographica 21:131-139.
Croswell, P.L., 1987. Map accuracy:
what is, who needs it, and how much is
enough? Papers from the Annual
Conference of the Urban and Regional
Information Systems Association Vol.
II., Fort Lauderdale, FL, pp. 48-62.
Dicks, S.E., and Lo, 3T.H.C., 1990.
Evaluation of thematic map accuracy in a
land-use and land-cover mapping program.
Photogrammetric Engineering & Remote
Sensing 56(9):1247-1252.