e Dossier Level
At this stage the final classification of the whole
declaration (dossier) is being made to “accepted”,
“rejected” and “doubtful”. Table 6 indicates the rules
for classified the dossier.
The identification of the land use in a first stage for each
plot was made carrying out supervised classification on
multitemporal images set. The results of the classification
were checked against ground samples different than the
ones used in the classification algorithm. The obtained
accuracy of the classification was better than 85% for any
classified land use, which were cereals, cotton, corn,
clover and vegetables.
For the identification of a specific use in a plot, the
accuracy of the classification for the specific use must be
greater than 75%, it must appear in an area bigger than
7096 of the plot's total area and the second found land-
use must be less than 20% of the plot's total area. This
was done by computing summary tables, resulted from
the overlay of the vectors on the results of the
classification.
Those plots that can not be controlled by the supervised
classification or have been declared for set-aside, should
be controlled by visual interpretation of the satellite
images on the computer screen on plot level. However,
all the plots were finally photo-interpreted to check for the
adjustment of their boundaries and their area, and the
automatic classification was finally used only to check
land use.
In AITO zone, for 300 applications which were randomly
selected, control was additionally carried out to check
whether the declared for subsidy plots were arable during
period of 1990 -1991, using multitemporal LANDSAT TM
images of those years.
CAPI (Computer Aided Photo Interpretation) was carried
out in a specially designed environment of the ERDAS
Imagine 8.2 software. The environment allows for the
simultaneous use of several windows, geographically
linked among them, to display the multispectral,
panchromatic and classified images with the vector
database which contains all necessary information and
provides entries for the user to add control results such
as control code (see Table 4) and measured area.
CAPI results were then processed by our diagnosis
software to perform control at group and dossier level.
Finally all the “rejected” and 20% of the “doubtful”
applications were to be checked by the Ministry of
Agriculture by ground truth survey and the results were
returned for statistical analysis.
The diagnosis software was also used to print three types
of lists, on plot, group and dossier level, that were
handled to the administration. These were accompanied
by printed maps in A3 size and 1: 10,000 scale, for
helping the on-the-spot controls. The maps contained the
SPOT-P image, the parcel boundaries (changes in
boundaries introduced by CAPI are indicated in a different
colour) and cartographic reference codes (parcels to be
field inspected are again indicated by code numbers of
different colour). All documents and maps were prepared
in a community level.
740
5. RESULTS
In dossier level, the results of Remote Sensing were 5094
accepted, 35% rejected and 15% doubtful.
By comparing the results of Remote Sensing and those of
the on-the-spot checks for 3,400 plots, differences in
land-use and area (more than 0.1 Ha) were occurred for
less than 5% and 3% respectively. Differences in land-
use are mainly caused from the delayed sawing or re-
sawing of some plots with maize (corn) cultivation caused
by abnormal weather conditions in the control zones,
while differences in area were founded in some plots
which were cartographicaly referred on ortho-photomaps
and the delineation of their boundaries were inaccurate.
6. REFERENCES
JENSEN J., 1986.
Processing Prentice Hall, New Jersey, USA, pp 379.
Introductory Image
GAF/GEOMET, 1991. by
Remote Sensing of some Agricultural Production,
Region GREECE, Final Report, Munich, GERMANY
Integrated Control
GEOMET, 1992b. Remote
Temporary Set-Aside and Oilseeds Vn Greece, Final
Report, Athens, GREECE
Sensing Control of
GEOMET, 1993b. Remote Sensing Control of Surface
Subsidised Arable Land and Forage Areas, Final
Report, Athens, GREECE
CHIESAC., TYLER W.,1994. Cubic
Convolution: ERIM Restoration for Remotely-Sensed
Beyond
Imagery, Earth Observation, Volume 3, Number 2,
USA
EAGGF,1995. RECOMMENDATIONS FOR
THE 1995 REMOTE SENSING CONTROLS, Brussels,
BELGIUM
ERDAS Inc., 1995. Erdas Field Guide, Third
Edition, Version 8.2, Atlanta, USA, pp. 628
GEOMET, 1995b.Remote Sensing Control of Surface
Subsidised Arable Land and Forage Areas, Final
Report, Athens, GREECE
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B7. Vienna 1996