PHOTOGRAMMETRIC ENGINEERING & REMOTE SENSING
November 2014
1021
I would like to bring your attention to any reference that I
used to the ASPRS mapping standard refers to the current
standard of 1990. A new mapping standard by ASPRS is
in its final stages and will be published soon. Once it is
published, the new standard should make it easier for
users to understand map accuracy and its relationship to
the image or ortho GSD as the standard is intended for
digital data.
3.
As for the method of determining the vertical accuracy
based on the GSD, traditionally in the past, we used
errors propagation based on the parallax equation
which takes into consideration flying altitude, parallax
measurements, camera focal length and air base among
other quantities to estimate horizontal and vertical
accuracy for certain photography. The subject became
more complicated considering we now rely on so many
other factors during the data processing and modeling
(see earlier listed factors) and not just the camera/
flight geometry. Manufacturers of digital cameras are
encouraged to provide their camera users with means
Table 2 Design parameters for large format digital metric cameras
Sensor
Focal length (mm)
Array size (pixels)
CCD size (um)
Flying Altitude (m)
Resulting GSD (cm)
Swath width (m)
ADS80
62.770
12,000
5.0
720
7.5
900
62.770
12,000
5.0
1,440
15.0
1,800
62.700
12,000
5.0
2,881
30.0
3,600
ADS100
62.500
20,000
5.0
938
7.5
1,500
62.500
20,000
5.0
1,875
15.0
3,000
62.500
20,000
5.0
3,750
30.0
6,000
DMC IIe 230
92.000
15552x14,144
5.6
1,232
7.5
1,166
92.000
15552x14,144
5.6
2,464
15.0
2,333
92.000
15552x14,144
5.6
4,929
30.0
4,666
DMC IIe 250
112.000
16,768 x 14,016
5.6
1,500
7.5
1,258
112.000
16,768 x 14,016
5.6
3,000
15.0
2,515
112.000
16,768 x 14,016
5.6
6,000
30.0
5,030
UltraCAM Eagle 80
80.000
20,010 x 13,080
5.2
1,154
7.5
1,501
80.000
20,010 x 13,080
5.2
2,308
15.0
3,002
80.000
20,010 x 13,080
5.2
4,615
30.0
6,003
UltraCAM Eagle 100
100.000
20,010 x 13,080
5.2
1,442
7.5
1,501
100.000
20,010 x 13,080
5.2
2,885
15.0
3,002
100.000
20,010 x 13,080
5.2
5,769
30.0
6,003
UltraCAMFalconPrime
(standard)
100.000
17,310 x 11,310
6.0
1,250
7.5
1,298
100.000
17,310 x 11,310
6.0
2,500
15.0
2,597
100.000
17,310 x 11,310
6.0
5,000
30.0
5,193
UltraCAMFalconPrime
(wide angle)
70.000
17,310 x 11,310
6.0
875
7.5
1,298
70.000
17,310 x 11,310
6.0
1,750
15.0
2,597
70.000
17,310 x 11,310
6.0
3,500
30.0
5,193
to estimate product accuracy during the project design
stage in a similar fashion to what the manufacturers of
LiDAR systems provided for their system users. Most, if
not all, LiDAR systems manufacturers provide the users
with horizontal and vertical accuracy estimates during
the project design stage based on the design parameters
entered by the users and the quality of the GPS, IMU,
and other system components. As far as I know, a robust
method of modeling all possible errors sources based on
sound errors propagation technique to relate image GSD to
certain accuracy may not exist today. Until such measure
is developed and accepted by the majority of users, the
community will continue utilizing the best practices that
were followed in the last couple decades. Such practices
were proved to be safe and productive.
The contents of this column reflect the views of the author,
who is responsible for the facts and accuracy of the data pre-
sented herein. The contents do not necessarily reflect the offi-
cial views or policies of the American Society for Photogram-
metry and Remote Sensing and/or Woolpert, Inc.
