International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part B-YF. Istanbul 2004
The data intergrated for the creation of this
cartographic background of the Municipality of X
Thessaloniki were two images taken by the
IKONOS-2 satellite (in UTM projection, zone 34,
ellipsoid WGS84, geodetic datum WGSS84) in
March 2000 showing the greater area of
Thessaloniki and a topographic map of the same where
area, scale 1:8000, obtained from the Municipality's
urban planning office. The two images were:
ag va X v u;Y (1)
b, b X tb.Y
y
x, y 7 GCP'S coordinates (TM87)
X,Y = GCP’S coordinates (UTM)
a; , bj 1=0,1,2 transformation parameters
. A panchromatic image with a resolution of A : : 7 : d
| meter( Fig. 1) * Geometric correction of each image, through a 2"
: : ; « s y 7 © » ^ c
. A multispectral image with a resolution of degree polynomial model. The total root mean
square of the reduction was RMS = 0.6629m for the
panchromatic image and RMS = 1.3404m for the
multispectral. Resampling for both images was
attained with the bicubic method. The equations of
the transformation used are:
4 meters ( Fig. 2)
x=a,+a,X+a,Y +a, X’ +a, XY+a.Y’ 2)
y=b, +b, X+b,Y +b, X* +b, XY +b.Y’
where x,y = GCP’S image coordinates (TM87)
X,Y = GCP’S image coordinates (UTM)
a; , b; 1=0,1,..,5 transformation parameters
= Registration of the multispectral image in the
panchromatic image with the help of a 2" degree
polynomial model and 22 control points. The
registration presented a total root means square of
0.8376 m (RMS = 0.8376 m). Also there was a
histogram matching of the multispectral’s histogram
to the panchromatic’s histogram, in the first
occasion, so that the two images would present the
same radiometry, while in the second occasion there
was no histogram matching between the two
images. Finally, the exact same geographic region
was cut off the two images, at the borders of the
municipality. Hereafter, the merging of the two
images — with — the principal components
transformation (PCT) was applied. The result was
the creation of two synthetic images.
Pu | The synthetic image in the first occasion where
histogram matching between the two images was
Figure 2. IKONOS MS (4m) attained is the following (fig.3).
2.2 Methodology
2.2.1 Creating the synthetic images: The specific
application through the process of the above data
was completed in two stages. The first stage
regarded to the preparation of the two satellite
images, which would compose the image that
constituted the cartographic background. The
complete procedure is described in Bussios N.,
Tsolakidis Y., 2003. The creation of the synthetic
image included:
* Mensurations of 34 ground control points
(GCP'S), with good allocation in the Municipality
of Thessaloniki with G.P.S.. The geometric model
used for the transformation of the points from
WGS84 to EGSAS87, was a general affine
transformation with 6 parameters. The equations of
the affine transformation are the following:
Figure 3. Synthetic image |.Municipality of
Thessaloniki.
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