PHOTOGRAMMETRIC ENGINEERING & REMOTE SENSING
April 2015
271
Table 3 Vertical Accuracy Standards for Digital Elevation Data
Vertical
Accuracy
Class
Absolute Accuracy
Relative Accuracy (where applicable)
RMSE
z
Non-Vegetated
(cm)
NVA at 95%
Confidence Level
(cm)
VVA at 95
th
Percentile
(cm)
Within- Swath
Hard Surface Repeatability
(Max Diff)
(cm)
Swath-to-Swath
Non-Vegetated Terrain
(RMSD
z
)
(cm)
Swath-to-Swath
Non-Vegetated Terrain
(Max Diff)
(cm)
X-cm
≤X
≤1.96*X
≤3.00*X
≤0.60*X
≤0.80*X
≤1.60*X
and other quality criteria for ten common vertical accuracy
classes, Table 4. To help users of the new standard during
the transition period, the new standard provides examples
to relate the ten vertical accuracy classes of Table 4 to their
equivalents contours intervals from legacy ASPRS 1990 and
NMAS 1947 standards as it is illustrated in Table 5. Contours
Table 4 Vertical Accuracy/Quality Examples for Digital Elevation Data
Vertical
Accuracy
Class
Absolute Accuracy
Relative Accuracy (where applicable)
RMSE
z
Non-Vegetated
(cm)
NVA
at 95%
Confidence Level
(cm)
VVA
at 95
th
Percentile
(cm)
Within-Swath
Hard Surface Repeatability
(Max Diff)
(cm)
Swath-to-Swath
Non-Veg Terrain
(RMSD
z
)
(cm)
Swath-to-Swath
Non-Veg Terrain
(Max Diff)
(cm)
1-cm
1.0
2.0
3
0.6
0.8
1.6
2.5-cm
2.5
4.9
7.5
1.5
2
4
5-cm
5.0
9.8
15
3
4
8
10-cm
10.0
19.6
30
6
8
16
15-cm
15.0
29.4
45
9
12
24
20-cm
20.0
39.2
60
12
16
32
33.3-cm
33.3
65.3
100
20
26.7
53.3
66.7-cm
66.7
130.7
200
40
53.3
106.7
100-cm
100.0
196.0
300
60
80
160
333.3-cm
333.3
653.3
1000
200
266.7
533.3
Table 5 Vertical Accuracy of the New ASPRS 2014 Standard Compared with Legacy Standards.
Vertical Accuracy
Class
RMSE
z
Non-Vegetated (cm)
Equivalent Class 1 contour interval
per ASPRS 1990 (cm)
Equivalent Class 2 contour
interval per ASPRS 1990 (cm)
Equivalent contour interval
per NMAS (cm)
1-cm
1.0
3.0
1.5
3.29
2.5-cm
2.5
7.5
3.8
8.22
5-cm
5.0
15.0
7.5
16.45
10-cm
10.0
30.0
15.0
32.90
15-cm
15.0
45.0
22.5
49.35
20-cm
20.0
60.0
30.0
65.80
33.3-cm
33.3
99.9
50.0
109.55
66.7-cm
66.7
200.1
100.1
219.43
100-cm
100.0
300.0
150.0
328.98
333.3-cm
333.3
999.9
500.0
1096.49
interval given in Table 5 is provided only for comparison
reasons and it should not be used in the new standard to
measure vertical accuracy as the new standard no longer
endorses the use of contour interval or map scale as indicator
for map accuracy.
