COMPARISATION OF SPATIAL ACCURACY OF DATA ACQUARIED FROM MONO
AND STEREO IMAGES :A CASE STUDY OF CAMPUS AREA KONYA -TURKEY
O. Mutluoglu 3 M. Yakar a H.M. Yilmaz b , F. Yildiz 3
a Selcuk University, Engineering and Architecture Faculty, Geodesy and Photogrammetry Department, 42075 Konya,
TURKEY - yakar, omutluoglu, fyildiz )@selcuk.edu.tr
b Aksaray University, Engineering Faculty, Geodesy and Photogrammetry Department, Aksaray, TURKEY -
hmyilmaz@aksaray.edu.tr
Commission IV, WG IV-9
KEY WORDS: High Resolution IKONOS Images, Feature Points, Geodetic Methods, Ortho Photo
1. ABSTRACT:
Nowadays, high resolution IKONOS images for map productions, local municipality studies, communications, agriculture, forestry,
energy and infrastructure, monitoring of environment, disaster management, determination of natural resources, pipeline,
transportation, security, defence and GIS studies. Accuracy of spatial is the most important factor in view of the map production
using IKONOS images.In this study, digital ortho photo maps have been produced using 1 m resolution mono and stereo IKONOS
images. Mono and stereo images have been covered the same area. Some feature coordinates have been measured from the produced
ortho photo maps of selected test area. The same feature points surveyed using electronic total stations according to geodetic methods.
Ortho photo coordinates and geodetic coordinates have been compared. Differences have been calculated and results have been given.
1. INTRODUCTION
Nowadays, satellite images have been used for many
applications intensively. For example, updating existing maps,
land use mapping, urban planning, disaster monitoring, and so
on. To use high resolution satellite images in such fields, they
had to be rectified. Rectification process is done by points,
which coordinates are known in both land and image. The
selected points may indicate either measured points in the field
or/and can be designated as visible points in images. These
points may represent; building comer, road cross, painting
objects, etc.
The launch of IKONOS by Space Imaging opens a new era of
high-resolution satellite imagery collection and also promotes
the mapping applications of satellite imagery. The IKONOS
satellite simultaneously acquires lm panchromatic and 4m
multi-spectral images in four bands with 11 -bit radiometric
resolution that are suitable for high accuracy photogrammetric
processing and mapping applications (Tao et al. 2004). Space
Imaging provides a broad category of mono and stereo products
including georectified, orthorectified and stereo imagery
products with different accuracy levels (Dial 2000, Grodecki
and Dial 2001). The specified horizontal accuracies of the Geo,
Reference, Pro, Precision and Precision Plus IKONOS products
are 25 m, 11.8 m, 4.8 m, 1.9 m and 0.9 m CE90 (Circular Error
90%), respectively.
Many investigations related to the accuracy of IKONOS
imagery by means of some photogrammetric process have been
reported so far. Zhou and Li (2000) showed the potential
accuracy (2-3 m) of ground points gained using simulated 1 m
IKONOS stereo images and the pushbroom imaging principle.
Fraser and Hanley (2003) achieved submeter accuracy using
one ground control point (GCP) for bias compensation in
IKONOS RFs. Toutin (2003) evaluated the potential, the
accuracy and the robustness of the 3D parametric model under
different conditions. It was concluded that 20 3-m accurate
GCPs were a good compromise to achieve a 3- to 4-m error in
the bundle adjustment, while 10 1-m accurate GCPs were
enough to achieve a 2- to 3-m accuracy. Wang et al. (2005)
presented four different models defined in both object space and
image space to refine the rational function derived ground
coordinates. It was demonstrated that if an appropriate model
and GCPs were used, ground point errors could be reduced from
5-6 to 1.5 m in horizontal and from 7 to 2 m in vertical
directions. Dial and Grodecki (2003) had tested Ikonos stereo
accuracy without ground control. They had achieved to absolute
accuracy at 6.2 m. horizontal, 10.1 m. vertical, and found out
the most relative accuracy results for points more than 3 meters.
Due to its superior geometric accuracy characteristics, IKONOS
satellite imagery is particularly well suited for large scale
mapping applications [Dial and Grodecki, 2002], [Grodecki et.
al., 2003]. As for geometric correction of high-resolution
satellite imagery, acquisition of ground control points is
important [Kadato and Takagi, 2002].
2. MATERIAL AND METHOD
2.1. Test area
Alaeddin Keykubat campus area of Selcuk University was
selected as the test area in order to compare. The campus area is
located from 20 km north of Konya city center which includes
10 faculties, 2 vocational high schools, dormitories, social
facilities such as sports centers, health centers, cafeterias,
shopping centers, etc (Mutluoglu, 2004). In this study, one pair
of stereo IKONOS imagery (acquisition date 30/01/2004) and
mono IKONOS imagery (acquisition date 03/05/2003)
covering Selcuk University Campus, in the northern part of
Konya city, were used (Figure 1).