Paper prepared for XII th Conference of Polish Society of Photogrammetry and Remote Sensing, Bialobrzegi, Poland, June 2002, ISBN 83-917952-0-9

1. TECHNOLOGICAL BOUNDARY OF ACCURACY OF ORTHORECTIFICATION
OF IKONOS AND QUICK-BIRD BASED ORTHOPHOTOMAPS
R.LACH, C.MISIUN, L.SKRZYPCZYK
pp. 216 – 230 XII th Conference of Polish Society of Photogrammetry and Remote Sensing, Bialobrzegi,
Poland, June 2002, ISBN 83-917952-0-9
Text of this article have been written Robert LACH, are different then
My contact data
they were in 2002
rlach@techmex.com.pl ,
in 2002 year. Disclaimer and
+48 605 695 064 mobile
comment on the first page were Therefore
+48 22 560 82 24 direct phone
added in 2003 and 2004 prior to current contact data are :
+48 22 560 82 00 secretary
Robert LACH
World Congress of ISPRS in +48 22 560 82 30 fax
GEOSPACE-PL
Istanbul. robertlach00@gmail.com
+48 500 739 777 mobile phone
DISCLAIMER
As it appears a lot of information noise; this article was submitted for review
to specialists of SPACE IMAGING LLC .
Precision Plus orthophotomaps production in Poland, some remarks of production
orthorectification of IKONOS imagery with usage of Rational Polynomial Coefficiencies
files for area of 30 000 km² for the needs of Integrated Administration and Control
System of European Commission in Poland
Description of the project refers to acquiring of archive imagery of SI EURASIA and
new collection of area of Poland from 2003 year. SI EURASIA passed us information
from 52 uncuccessful METEOSAT passes and 16 succesful IKONOS passes.
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2. As there appears a lot of "information noise" in Poland as to possible ortorectification of VHR data,
the authors wish to share the results of their work - they have performed all by themselves and that
refers to fully domestic production of satellite ortophotomaps prepared for over 3,169 km² in 2002 -
with both the Polish and international photogrammetric family.
There had appeared international publications referring to the problem several years before IKONOS
and then QUICK BIRD systems were launched and they were often full of speculations as to expected
accuracy of ortophotomaps. After IKONOS was launched, there appeared another tide of
publications in reference to self-dependent attempts to orthorectify the Carterra GEO products,
which could hardly be successful due to lacking access to the mathematical model of IKONOS sensor 1
- despite their correct mathematical approach with application of precise model to orthorectification
(rational polynomial coefficiences). The error results in RMSE terms used to range to 3-4 m.
 Application of the IKONOS sensor model, implemented, for the first time upon consent of
SPACE IMAGING Inc., by ERDAS,
 a collection of images for Poland with not exceeding deviation of 180 from nadir,
 fulfilling of strict requirements of SPACE IMAGING INC 2. as to accuracy of the control
points measurement (GCPs.) with application of GPS technology,
 application of Digital Elevation Model (characterised with accuracy of height delimitation of
2-3 m) to the orthorectification process,
made it possible to produce orthophotomaps with the RMSE value below 1 m. Production of the
ortophotomaps has been realised in full by a Polish team : Baltyckie Centrum Systemow Informacji
Przestrzennej [the Baltic Centre for Spatial Information Systems] thanks to logistic technological and
financial support of the TECHMEX S.A. and an open-minded position of Space Imaging Eurasia.
A short introduction to the VHR systems competition
A delayed start of that prognosticated era of VHR satellites, which began with placing
IKONOS 2 system on the orbit in 1999, has been more and more dynamically advanced.
However, the users' expectations as to the quality of VHR satellite data have not been satisfied
yet by the EROS satellite system the information content of which hardly differs from the
KOSMOS system KVR-1000 data functioning on the Polish market. Launching the Quick
Bird system in October 2001 will advance origination of the VHR imagery market, not earlier,
however, than in the perspective of 2-3 years from 2002 on as at that time the systems are
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3. expected to start their real competition as far as their archives of metropolitan cities areas are
concerned. Efficient use of the VHR satellite system does not depend on resolution itself but
on the access to the wanted data on the market first of all. Meanwhile, the archives of images
of Poland that are available in Internet - of the Digital Globe's Quick Bird system - show that
on September,17th 2002 there are only 57 images characterised with less than 20% cloud
cover. In consideration of the speed of growth of archive of the IKONOS system with the
capacity to register large areas of interest (AOI) growing even up to four times bigger than
that of Quick Bird (Kurczynski, Wolniewicz) as well as the process of establishing of the
Polish archive of IKONOS system for 3 years now - the fact of disproportion between the
archives of IKONOS and of Quick Bird in Poland is not to be wondered at. Meanwhile,
SPACE IMAGING Inc. started constructing IKONOS BLOCK II system that, in 2004, is
going to have resolution of 40 cm and it seems that in two years time IKONOS and IKONOS
BLOCK II joint collection capacity will be at least 6 times of Quick Bird.
DEM produced from the IKONOS stereopair and the ortophotomap of Presision Plus
class as the first in Poland.
Having heard a lot of "information noise" in Poland as to the fact whether VHR imageries can
give a product as precise as to make the RMSE value smaller than 1 m and - having had no
access to the sensor model yet - in 2001we purchased Precision Plus orthophoto from SPACE
IMAGING Inc. We acted on behalf of the Municipality of Bytom that placed an order with us
to perform a detection of changes by comparing ortophotomaps of 1997 and 2001. SPACE
IMAGING Inc. requested us to measure only GCPs (ground control points) only and produced
a Numerical Terrain Model from the IKONOS stereogram with 6 meters post spacing (using a
Stereo Analyst module of ERDAS Inc.) and they next sent us imagery material after it was
ortorectified. The report on ortorectification process showed value of RMSE = 0.9 m. After
the ortophotomap sent by SPACE IMAGING Inc. was overlapped over the ortophotomap of
Bytom, performed in Poland by OPGK Olsztyn) on the basis of aerial photos from 1997, the
two ortophotomaps visually fitted together and only the radiometry of IKONOS' imageries
distinguished itself with more "lively' colours than the ortophoto taken from the PHARE
program aerial photographs. In the course of technical acceptance of the product in the GIS
unit of Bytom Municipality there cadastral data were overlapped onto the IKONOS
orthophotomap. Result, shown below proves that cadastral data (earlier created with
application of DGPS measurements asr fitting together with the IKONOS-based orthophoto.
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4. [the ortophotomap of October 2001 showing the borders of lands and building contours in
Bytom. Scale 1: 3,500, RMSE value of 0.9m]
IKONOS DATA ORTORECTIFICATION TESTS
An independent ortorectification of the Carterra GEO data with an IGM (Image
Geometry Model) model
Having carried out those tests and purchased the programming for independent
ortorectification of the IKONOS imageries from ERDAS Inc., we decided to perform
ortophotomaps of Precision Plus class by ourselves. On March 8 2002, Mr. Murat Erciyes,
President of SPACE IMAGING EURASIA had a meeting with the authorities of the National
Office of Geodesy and Cartography and Mr. Aleksander Bentkowski - President of Agency for
Restructuring and Modernisation of Agriculture. Tests of the IKONOS system that were to
include testing different kinds of land - from almost a flat one to those of big height variety -
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5. were decided to be carried out. The Polish Presidents of GUGiK (General Surveyors Office)
and ARMA (Agency for Restructuring and Modernisation of Agriculture) did hope to receive
so accurate a product that might satisfy both the IACS accuracy requirements and the accuracy
requirements for modernisation of the cadastral system with application of photogrammetric
technologies. Shortly speaking, the question consisted in performance of ortophotomaps of the
biggest possible accuracy - even of 1:5,000 scale. Additionally, the purpose of testing was also
to check whether, in the course of one passage, the system would register several adjacent
stripes of photographs in order to optimise the way of collection of IKONOS . On April 4
2002 SPACE IMAGING EURASIA registered images of 1150 sq. km of the Nowy S¹cz
administrative district area that had been chosen due to big overheights there (the lowest point
in the district is 200 m high and the highest - 1200m).
DETERMINATION OF ACCURACY of APPLIED DIGITAL ELEVATION MODEL.
The D.E.M. delivered by external partner was applied for ortorectification. Two D.E.M.s
were compared from the area surrounding Debrzno in the administrative district of Czluchów
– and are shown below. This DEM. was compared with the one performed for Debrzno from
the photographs of PHARE LIS 9206 program in SoftPlotter v.1.3. The area of about 36 sq.
km surrounding Debrzno was examined. The area is diversified as to the relief, the differences
in height being from 135 m to 178 m.
DEM delivered by external source on the left, DEM created from serial photogrammetric photos
( 1: 26 000 scale) on the right
Digital Elevation Model provided by external partner was converted to ASCI file. Resulting file was
imported into Microstation package. Blue lines of DEM sections were defined in 500 meters intervals
on from each other. Profiles were generated in Microstation. Test was executed on 3739 points ,
placed in 20 meter distances, grouped in 13 profiles. Each profile included 200 measured points.
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6. Results :
RMSE 2.65
NSSDA 5.20
Max. odchyłka 20.24
Min. odchyłka -6.68
0 - 0,5m 1045
1 0 - 1m 1862
2 1 - 5m 1737
3 5 - 10m 70
4 >10m 68
Accuracy of determination of z coordinate was better than one meter for 50 % of compared z
points as shown above. Preliminary test proved that 96 % of points of checked sample have z
accuracy – better than 5 meters.
Test No.2.
The same DEM sample was checked again in different way. Tested DEM with 20 meter post
spacing was converted from original file to ACSI format file. ASCI file was imported to
ERDAS IMAGINE 8.5.v. Sample DEM was compared with DEM produced from aerial
PHARE program photos, but these DEMs were delivered in different coordinate systems.
After unification of projections and coordinate systems both files were compared, where each
z values from one DEM file were substracted from z values of second DEM file. Test was
executed for DEM 165 248 points with 20 meter post spacing.
Results :
RMSE 1.91
Rozk³ad procentowy ró¿nic
NSSDA 3.75
wysokoœ ci
Max. odchyłka 15.24
Min. -19.86 1%
Odchyłka 9% 0%
0 - 1m
0 - 0,5m 41564
14%
1 - 2m
1 0 - 1m 76571 47% 2 - 3m
3 - 5m
2 1 - 2m 48230 5 - 10m
3 2 - 3m 23086 >10m
4 3 - 5m 14842 29%
5 5 - 10m 2308
6 >10m 211
Three classes of determination of z accuracy (green, light yellow and orange), within range of
1-3 meters errors form 92 % of checked DEM sample.
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7. Test No.3.
The aim of the test was to determine differences of location of analysed terrain details for
photos orthorectified on the basis of one and the other DEM. Two orthorectification processes
were run, using different DEMs. Later differences between resulting images were measured in
ERDAS IMAGINE, after orthorectification in the same software environment.
Results :
basic DEM Compared DEM RMSE
Nr X Y X Y różnica H dX dY dX 2  dY 2
Próbki
1 3510473.42 6003560.43 3510473.70 6003560.43 0.63 -0.28 0.00 0.28
3 3512706.63 6002257.10 3512706.49 6002257.52 0.46 0.14 -0.42 0.44
16 3508956.00 6001406.41 3508956.35 6001406.77 0.56 -0.35 -0.35 0.50
2 3512819.75 6002610.88 3512818.77 6002611.02 1.18 0.98 -0.14 0.99
6 3513496.60 6002775.67 3513497.25 6002775.28 -0.94 -0.65 0.39 0.76
13 3511764.34 6003508.14 3511763.96 6003508.14 0.99 0.37 0.00 0.37
15 3509259.43 6001342.26 3509259.23 6001341.65 -1.08 0.20 0.61 0.64
7 3512790.99 6002125.73 3512791.69 6002125.16 -2.14 -0.70 0.57 0.90
8 3512028.98 6002205.98 3512029.28 6002206.14 -2.06 -0.30 -0.16 0.34
12 3511673.58 6003466.58 3511673.10 6003466.58 1.99 0.48 0.00 0.48
10 3508671.23 6001889.33 3508673.11 6001890.01 3.01 -1.88 -0.67 2.00
11 3511502.19 6003257.71 3511501.80 6003257.94 3.20 0.38 -0.23 0.45
4 3513389.03 6002851.19 3513392.44 6002850.05 -4.31 -3.41 1.14 3.60
9 3511971.94 6002026.77 3511970.87 6002028.32 4.03 1.07 -1.55 1.89
14 3511848.81 6005095.52 3511847.67 6005094.00 4.09 1.14 1.52 1.90
5 3513609.47 6002833.79 3513619.61 6002831.06 -18.43 -10.14 2.73 10.50
Orthorectification of IKONOS scenes begun for several different landscapes after these initial
DEM tests. Several different test areas were selected from almost flat to mountain-type area.
We also wanted to test ability to register IKONOS imagery in different modes of collection,
including collection of each individual scenes, two-image strips collection, three image-strips
collection and four image-strips collection. These ways of collecting were applied during
testing process to 4 TEST AREAS.
TEST AREA 1 - Krasnik
First image of Krasnik village was acquired from Space Imaging Inc archive, since at the
beginning of testing process SI EURASIA did not have imagery for southern area of Poland,
characterized by large number of very small farms. Therefore we have purchased scene from
SI Inc archive , collected with viewing angle of less than 18 º angle from nadir, delivered to us
together with rpc files. (GeoOrthoKit)., registered on June 3rd of 2001. Number of GCPs was
determined on the basis of former findings of IKONOS orthorectification. MSPM program of
Ashtech was used for analysis of number of satellites and their geometric configuration.
Project of location of GCPs was prepared and 4 points of national POLREF network were
selected as tie points. (numbered 1701, 1802, 1803 and 2808). Twelve (12) points were
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8. measured using static method on the basis of reference points on 2002-03-20, using 4 GPS
Ashtech Z-XII and Ashtech Z-Surveyor receivers. Tropospheric correction was applied for
standard meteo conditions. Minimal elevation angle was set for 15 º. Rigorous eualization of
network was realized with usage of FILLNET program of Ashtech. Results were achieved in
WGS-84/ERTF’89.
B & L coordinates received were transformed from WGS-84 system to Krasowski 1942
(Pulkovo) on the basis of 4 common points of POLREF network .
Orthorectification was performed with usage of ERDAS IMAGINE 8.5.version with
application of OrthoBase module. Used DEM had 20 meter post spacing. Results achieved at
control points 12 CGPs were checked and then, after removing of worst point were
recaltulated again on 11 GCPs. Obtained result is shown on next page in the form of window
from part of ERDAS Imagine orthorectification report.
RESULTS ACHIEVED : RMSE received for 1 IKONOS scene = 0.8661 m
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9. TEST AREA 2 – Gostynin
Two image strips were collected on April, 7th , 2002 for area of relatively flat Gostynin area (central-
northern part of Poland ) of total area of 583 km².
20 meter post spacing DEM was used for orthorectification. GCPs were collected in similar way,
remembering about fulfilling strict accuracy requirements of SPACE IMAGING Guidelines for CGP
collection . These guidelines require to collect CGPs for most precise orthorectification with
planimetric accuracy better than 20 cm and “z” accuracy better than 60 cm.
RESULTS ACHIEVED :
(for particular image strips)
image id 1: RMS Errors for 28 GCPs: x: 0.2952
y: 0.2603
total: 0.3936
image id 2: RMS Errors for 24 GCPs: x: 0.2922
y: 0.3295
total: 0.4404
image id 3: RMS Errors for 23 GCPs: x: 0.3117
y: 0.4108
total: 0.5157
TEST AREA 3 – Nowy Sacz County
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10. Three image strips were collected on April, 4th, 2002 for Nowy Sacz County, for 1150 km²,
during one IKONOS pass over the area. Nowy Sacz county is located in the south of Poland,
bordering with Slovakia . It was most difficult area for orthorectification, since difference in hight at
the territory of the county are larger than 1000 m. Lowest point has 200 meters above the sea level,
the highest has more than 1200 m . Six images were orthorectified in one block, with usage of 53
GCPs. First stage of work was orthorectification of panchromatic imagery. GCPs causing greatest
errors were rejected. Next stage of work lead to creation of pseudo-natural color composition and
orthorectification of multicpactral data. Last phase of work was merging of panchromatic and
multispectral imagery with application of PCA method.
RESULTS ACHIEVED :
Image accuracy for control and check points for each scene:
image id 1: RMS Errors for 13 GCPs: x: 0.8224
y: 1.1841
total: 1.4416
image id 2: RMS Errors for 9 GCPs: x: 0.7305
y: 0.7736
total: 1.0640
image id 3: RMS Errors for 10 GCPs: x: 1.0780
y: 0.9510
total: 1.4375
image id 4: RMS Errors for 10 GCPs: x: 0.9687
y: 0.7371
total: 1.2173
image id 5: RMS Errors for 7 GCPs: x: 0.6371
y: 1.4884
total: 1.6191
image id 6: RMS Errors for 6 GCPs: x: 0.0000
y: 0.0000
total: 0.0000
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11. Total image RMSE = 1,2866 m
All works related to image collection, delivery to Poland, GCP collection,
orthorectification, mozaicking took only two weeks.
Resulting orthorectified naighbouring scenes. Please notify this is not a mozaicked orthoimagery, but
only set of two orthorectified scenes. Border between scenes may be observed in the forest area in the
southern part of image (at its centre). Currently cadastral records existing for part of the county are
overlapped over IKONOS orthophoto.
11/14

12. TEST AREA 4
Drawsko Pomorskie area
Four adjacent IKONOS strips, results in review by Military Intelligence Directorate
of Polish Army General Staff
CONCLUSIONS:
1. Registration of IKONOS imagery should be taken at 18o deviation angle from nadir
to produce ortophotomaps of RMSE <= 1 m,
2. Measurement accuracy of GCPs should - according to the technical instructions of SPACE
IMAGING Inc. and SPACE IMAGING EURASIA - be better than 20 cm (x and y) and better
than 60 cm vertically to make the summary error of measurement and point determination not
exceed 0.5 m (x,y) and 1 m (z)
3. Application of Terrain Numerical Model and post spacing of 20 metres as well as height
determination accuracy of 2-3 metres makes possible the domestic production of Precision
Plus class ortophotomaps where RMSE error is better than 90 cm.
4. The mode of registration of a bigger area (3 or 4 stripes of photographs one after another) in
the course of one route of the satellite (Objects: Nowy Sacz and Drawsko Pomorskie), tested
in 2002, shows the optimum way of registering the area of Poland.
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13. 5. The ortophotomaps already produced do satisfy both the accuracy requirements of the
European Union (EC Directive No 1593/2000) in reference to construction of ortophotomaps
and Land Parcel Identification System within the Integrated System of Administration and
Control as well as geodetic-cartographic regulations referring to the accuracy of the
ortophotomaps for the cadastral purposes for scale 1: 5000
Literature
Kaczynski R., Ewiak I., Ren Wei Chun, Yang Ming Hui, 2001 "Evaluation of Panchromatic IKONOS
Data for Mapping, Geodesy and Cartography", Vilnius, Vol. XXVII, No 4, pp 157-160
Bruno Biagini, Riccardo Nasini, 22-23 March 2002, EURIMAGE European Resellers Meeting, Roma
Zdzislaw Kurczynski, July 2002, Wies³aw Wolniewicz "VHR satellite imagery systems" Part I pp 18
- 22 GEODETA
Zdzislaw Kurczynski, Wieslaw Wolniewicz "VHR satellite imagery systems" Part II What is the
pixel below 1 m" pp 26 - 30 GEODETA, August 2002
Ryszard Preuss, Zdzislaw Kurczyñski "Conception of production of a ortophotomap of Poland for the
purposes of identification of land parcels - LPIS" pp 6 - 10 GEODETA, August 2002
Jan Konieczny, September 2002 "National System of Identification of Farms and Stock, the Polish
IACS and LPIS, Quickly, Properly, Cheaply ?" pp 8 - 11, GEODETA
Robert Lach, Murat Erciyes, September 2002 "Our Movement Now" pp 12 - 14, GEODETA
13/14

14. Tao C. Vincent, Yong Hu, Steve Schnick, 2002 "Photogrammetric Exploitation of IKONOS imagery
using the Rational Function Model", ASPRS Congress, Washington
Olivier Leo, Guido Lemoine, Jacques Stakenborg, 2001 "Discussion Paper on Land Parcel
Identification System v. 1.4.< Ispra, Italy
European Council Regulation No 1593/2000 of 17 July 2000.
1
(T. Toutin, Ph. Cheng, R. Kaczynski)
2
QA-042, Rev D, 11/28/00, GCP Specifications, Space Imaging proprietary
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