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International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Volume XXXIX-B7, 2012
XXII ISPRS Congress, 25 August — 01 September 2012, Melbourne, Australia
ese
Digital Orthophoto é
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Digital Elevation Model ; $-
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Figure 4. (a) Digital Orthophoto and Digital Elevation Model for Proposed Algorithm; (b) Digital Orthophoto and Digital
Elevation Model for Google Earth Coordinates
Linear Graph X Coordinate
Linear Graph Y Coordinate
Linear Graph Z Coordinate
(Onboard GPS) (Onboard GPS) (Onboard GPS)
seu VIG GES RT 1 362600 s 38
R220.999 a 162400 = 2
621000 = = y = 0.809x + 2.786
A 162200 j 2. T
620600 a A R°-0887 af.
= ge 5 s a oto
Ë 620600 ; 9 161800 9 pn 1
à à 3 Roe
2 © 5 ® 4
3 620400 § 161600 $ x e #
- i Mean AE :5.733 : 161400 Mean AE : 8.064 uo :
520200 ertet SHE RN Min AE : 0.497 Mir AE : 0.355 : Mean AE : 0.526
à ber pot NE ES 161200 Max AE : 20.375 NE eei
ser # : 161000 mum
619800 160800 0
519800 620000 620200 620400 620600 520800 62:000 621200 ! 180500 161000 381500 162000 1625C0 1863000 0 5 10 15 20 25
Actual Actual Actual
(a)
Linear Graph X Coordinate Linear Graph Y Coordinate Linear Graph Z Coordinate
(GE GCP) (GE GCP) (GE GCP)
621200 162600 20
v7 1004x - 3004. V=0.391x+ 1368. of y=0.811x 1 2.773 s.
R^» 0.999 Pa 162400 s nins. 1-052 4 X
621000 R? = 0.999 as a
i 162200 : 15 a t *
SEE P ud 162000 ^ = "y
Y 620600 #7 Tomo 6 H nF
i a’ à A à 10 E
2 QU ir = = => à
i adios 2 161600 # 2 à 2
Mean AE : 8.023 481400. beet retro un reer. Mean AE : 8.009 Mean AE : 0.617
520200 m P MinAE:0.052. — 0 7 a i oe qe des -i Min AE : 0.007
s Min AE : 0.095 161200 d i Max AE : 16.605 5 in AE : 0.
T ert eds J AE : 36.25 # ide: | Max AE : 3.507
620000 / Max AE : 36.25 161007 p ie "
619800 160800 0
619800 620000 620200 620400 620600 620800 621000 621200 186500 161000 161500 162000 162500 163000 o 5 10 15 20 25
Actuaf Actual Actual
Figure 5. (a) Linear graph X, Y, Z coordinates for GPS onboard; (b) Linear graph X, Y, Z coordinate for Google Earth (GE) coordinates.
Figure 5 shows that most of points fit in the line 1:1 (red line
on the graph) for X coordinate and it can be concluded that x
coordinates for GPS onboard are precise while x coordinates for
Google Earth (GE) control points are less precise because some of
the points are located higher and lower than line 1:1. Most of
points are located exactly in line 1:1 for Y coordinate, thus it can
be concluded that y coordinates for GPS onboard and GE control
points are precise and reliable. The situation is different for Z
coordinate because some of points are randomly located above
and below line 1:1. However, there is a slight difference between
GPS onboard and GE control points in which the result of GPS
onboard showed better precision compared to GE control points.
In contrast, proposed algorithm gives better precision compared to
GE control points. However, the detail of points located on line
1:1 can be viewed if the linear graph is shown in a larger scale
image size.
5. DISCUSSION
497
In this study, the accuracy of photogrammetric product was
assessed based on root mean square error, mean absolute error
and linear fit equation and determination of correlation coefficient
for each result. The general formula of linear fit equation is
illustrated in Equation 8.
y=a+bx (8)
Where a,b = coefficient data
As mention in section 3 and section 4, there are two cases in this
study. The first case is by using GPS onboard as control point and
integration with proposed algorithm in image registration and the
second case is image processing by using control points acquired
from Google Earth coordinates. Both results are divided into X, Y
and Z coordinate. Therefore, the result of each coordinates can be
assessed individually. The error distribution of each coordinate
for GPS onboard and Google Earth coordinate can be viewed
graphically in Figure 6. Figure 6 shows the results of
