anbul 2004
lows in the
r the visual
and debris
t enhanced
t a scales
00, and to
eters, such
n yield a
recognition
nce of the
traditional
ntially risk
of SPOT 5
bined with
vices have
Space and
ular during
e Southern
dillon, S.,
lgalda, J.,
e acquired
TUS scenes
O pairs of
e taken as
às possible
er 5 days
more days
used as a
generated
their very
to existing
'eas which
lighted the
1annel and
from three
'ogramme,
overing 60
‘the 2003
SPOT. 5)
sie. more
radar and
U obtains
areas and
the use of
ronmental
| Baden-
Aastrand,
P., de Roeck, E., and Leo, O., 2004). For such control, VHR
satellite images were required to count the number of trees, to
measure the declared area and to draw conclusions concerning
the age by interpreting the treetops.
The test has been performed over 551 parcels. A SPOT 5 25 m
resolution and a QuickBird 60 cm resolution panchromatic images
were visually compared to an orthorectified airborne image of May
2001, with 2 m resolution.
This comparison showed that the SPOT 5 2.5 m panchromatic
data is sufficient for a definitive tree counting if the trees are
clearly separated, which is generally the case for this type of
extensive orchards. But tree counting is no longer possible
when the trees are rather close to each other and their tree
crowns seem to fuse together.
In some complex situations (around 20% of the declared fruit
orchards), such as fruit orchards near buildings or tree rows, a
blur effect leads to non-interpretable situations both on the
ortho-photo an on the SPOT 5 image. In these cases, either a
better resolution is required (i.e. QuickBird imagery) or field
inspection, as foreseen by the general control with Remote
sensing methodology, has to be done. Another complementary
strategy recommended is to systematically check the eligibility
of the orchards on the basis of very high resolution satellite
imagery, when the farmer applies for the first time to the AEM.
The use of SPOT 5 data is finally recommended for a regional
fraud detection approach, providing an element for the selection
of the sample to be controlled (risk analysis). In this case a
classification of SPOT 5 data could be very efficient to check
for a huge number of parcels, the compliancy with . some
specific and visible commitments such as autumn green cover
or crop rotation. The interest of such approach is increased by
the fact that these commitments are dynamic and outside the
main cropping season. They are consequently already poorly
controlled by traditional inspections.
3.3.2 Forestry
Forest monitoring is one of the thematic domain where benefits
linked to SPOT 5 enhanced resolution and unchanged
multispectral information content (specifically SWIR and NIR
channels) are the most salient.
The SAVP study performed by METRIA on boreal forest
demonstrates that, compared to Landsat-7 or SPOT-4 images,
additional forestry features can be detected, identified and
mapped in SPOT-5 2.5 m colour images (Rosengren, M. G.,
and Willén, E., 2004.).
Information brought by SWIR channel is of highest interest for
foresters as it is correlated to density, timber volume and tree
height in coniferous forests. Therefore METRIA developed a
merging technique producing four enhanced multispectral
channels at 2.5 m resolution, including SWIR. Such 2.5 m
colour image permits to detect the presence of seed trees left on
new clear-cut area. Line patterns resulting from thinning by
harvester machines could also be easily identified on 2.5 m or
5m colour images.
Very precise clear-cut mapping (minimum size mapped: 0.5 ha)
could be reached using change detection between SWIR
channels acquired at two dates (SPOT 5 and Landsat-7 SWIR
bands). Within these clear-cut areas, it is possible to generate a
seed trees map, by thresholding the SPOT 5 original 10 m
resolution SWIR channel. Stratification and planning of field
International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part BI. Istanbul 2004
visits will benefit from this result, as in field validation gave
good results.
In Sweden the main limit is meteorological conditions. SPOT 5
alone cannot meet the need for yearly nation-wide cloud-free
coverage. Nevertheless, it can be noted that in 2003, Spot
Image delivered more than 200 scenes on Swedish forests,
confirming its excellent acquisition capability.
Another study performed by SERTIT on a French forest
(Haguenau, Alsacian forest), demonstrated the relevance of
SPOT 5 images for forest mapping (Clandillon, S., Yesou, H.,
and Meyer, C., 2003).
After the December 1999 storm, a large part of Haguenau forest
was devastated. In 2002, SERTIT tested the use of SPOT 5 data
to update the damage maps and evaluated their usefulness in
forest management, in relation with forestry end-users.
Damage zones were mapped accurately by comparing SPOT 5
10-m colour image before (simulated image) and after the
storm. Results for forest parcels were very close to those
obtained by the French National Forestry Office (ONF),
working at a scale of about 1:10,000. In comparison with a
similar data set acquired by SPOT 4, detection errors using
SPOT 5 data were reduced by half.
In addition, SPOT 5 data were assessed for their potential in
forest management. Regenerated areas, young coniferous
stands, paths, firebreaks and forest works can be clearly
identified on 2.5 m data. Forestry professionals such as forest
owners, state and private administrators, and foresters very well
received these results.
3.4 3-Dimensional visualisation
This SAVP investigation by the French Air Force, validates the
concept of a flight simulation system dedicated to the pilot's
familiarization with the natural environment that they will face
in their future missions (Hernoust, F., and Cances, M., 2004).
The tested 3D-visualisation solution integrated a system light
and easy to maintain and to operate by a pilot with no exterior
assistance, and a SPOT 5 3D-database, on a limited area around
an airport, allowing multi-scale and multi-resolution display,
from 10 to 2.5 m resolution.
Experimented pilots and trainees have been briefed on the main
controls of the tool, and then they have flown freely over the
database. The interest was proved through the first evaluations.
Cost is undoubtedly a key factor underlying increased use of
SPOT 5 imagery, eventually merged with aerial images, and
enriched by aeronautical data into flight simulators or simpler
but realistic visualization systems.
Among the operational users of SPOT 5, the US Air Force
(USAF) has validated the use of SPOT imagery in mission
planning. SPOT 5 data are used in the F-16 flight simulator at
Luke Air Force Base, Arizona. Customers who have turned to
SPOT include Lockheed Martin, CAE, Flight Safety
International, Frasca International, Multigen Paradigm, Terrex
and BAE Systems.
4. CONCLUSIONS
SAVP results (and current amount of Spot Image sales and
repartition between Spot 2-4-5!) demonstrate that Spot is a real
success, due to its 2.5 m resolution combined to unchanged
