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The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences. Vol. XXXVII. Part B4. Beijing 2008 
Usually in cartographic or surveying approaches (e.g. parcel 
area determination) data quality (e.g. accuracy of calculated 
area) is estimated by RMS. National regulations determine 
acceptable discrepancies according parcel area, elongation or 
calculation method. In case of visual interpretation of remotely 
sensed imagery not only factors mentioned above are important. 
The results are influenced by the process of photo interpretation 
as well. In this in mind we decided to test another approach - 
ISO 5725-2 standard usually applied to chemical measurements. 
ISO 5725-2 gives “the basic method for the determination of 
repeatability and reproducibility of a standard measurement 
method”. It is typically designed for interlaboratory 
experiments in order to estimate repeatability and 
reproducibility of measurement method (of chemical contents 
for example), but it can also be used for other purposes. 
Hejmanowska et al. (2005) presented its application to 
repeatability and reproducibility assessment of orthophoto- 
based measurements done during the experiment for validation 
of land parcel areas measurement methods. Results of the 
research were presented in the final report of the project 
supported by Joint Research Centre (JRC) in Ispra in Italy 
where. In the report the huge experiment of agriculture parcel 
measurements with accuracy assessment was described. 
Statistical analyses involved in the project, based on ISO 5725, 
were inspired by S.Kay and J.Delineé from JRC. In a typical 
application of ISO 5725-2 standard for basic interlaboratory 
experiment, samples from q batches of materials representing q 
different levels of the content to be measured are sent to p 
laboratories. Each laboratory obtains n replicated results under 
repeatability conditions for each of the q levels. In the case of 
photo interpretation several test areas should be measured on 
different days by different operators. 
In a typical interlaboratory experiment critical examination of 
the data is based on a “pooling factor”: the observations are 
grouped according to this factor and mean and standard 
deviation within a given group is compared to the means and 
standard deviations within other groups. Typically the pooling 
factor is the factor “laboratory”, because in each laboratory 
replicated results are obtained under repeatability conditions. 
For remote sensing applications measurements made by the 
same operator on several days can be considered as made under 
repeatability conditions. As a consequence, the data should be 
pooled by operators. 
3. TEST AREA AND DATA 
Measurement experiment was performed applying the remote 
sensing images covering region near Cracow, on the south of 
Poland. Two kinds of data were applied: IKONOS PAN (called 
PAN in the paper; pixel size of lm) and colour IKONOS PAN- 
SHAR (called RGB in the paper; pixel size of lm) registered 
7.05.2003 and delivered as 16 bits GEOTIF. Besides, 
panchromatic airborne orthophoto (0.2m - pixel size) generated 
from photographs in scale of 1:13 000 was applied as a 
reference. 
Test area is composed of 6 rectangles of 300x300 m (10x10 
Landsat pixels): 2 dense urban (3 rd and 4 th test area, ca. 60% of 
impervious surface), 2 industrial (2 nd and 5 th , ca. 80% of 
impervious surface and 2 suburban (1 st and 6 th , ca. 30%), 
(Figure 1). Test area no. 1 with 30 m grid overlaid on the 
IKONOS (RGB) image is shown as an example on the figure 
(Figure 2). 
sv'iRMmmü 
Figure 2 Test area no. 1 with 30m grid overlaid on the image, 
right also with reference area of impervious surface digitised on 
air orthophoto (0.2m - pixel size). 
4. METHODOLOGY 
Impervious surface area was digitised on the test area 1, 3, 4 
and 6, and pervious surface in the case, when the surface is 
much smaller then impervious one (test area 2 and 5). Two 
groups of operators were chosen: 3 specialists and 3 beginners. 
Operator digitised firstly IKONOS PAN (3 times) then 
IKONOS RGB (3 times). Finally, specialist digitised 
ortophotomap with pixel size of 0.2 m and reference impervious 
surface was collected for each of six test area (Figure 2 right). 
Data analysis is composed of 2 parts: accuracy analysis of 
photointerpretation of IKONOS images (PAN, RGB) and 
research of its influence on its averaging in 30 m Landsat pixel 
size. 
4.1 Part 1 - accuracy analysis of IKONOS 
photointerpretation 
Results of the remote sensing images photointerpretation could 
be compared in different aspects: object recognition (object 
recognised or no), variation of the border shape or variation of 
area of the recognised object. Photointerpretation is both, time 
and cost consuming, so there is difficult to find in the literature 
some information about accuracy of the process, based on 
fotointerpretaion made by many operators. Usually 
fotointerpreatation is made once, and it is treated as a reference. 
One can assume, that the photointerpretation process is biased 
by operator, and accuracy depends on the experience of the 
person performing interpretation. In approach basing on the 
remote sensing, accuracy is usually determined by RMS, 
calculated from differences between mean value of