GEOG 892
Geospatial Applications of Unmanned Aerial Systems (UAS)

Horizontal Accuracy Standards for Geospatial Data

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Some of the highlights of the new ASPRS Horizontal Accuracy Standards for Geospatial Data are the following:

  1. Unlimited horizontal accuracy classes:
    The new standard was designed to fit any horizontal accuracy requirement no matter what technology, current or future, is used. Table 3 represents the new ASPRS horizontal accuracy classes.
    Table 3 The new ASPRS horizontal accuracy classes
    Horizontal Accuracy Class RMSEx and RMSEy (cm) RMSEr (cm) Horizontal Accuracy at 95% Confidence Level (cm) Orthoimagery Mosaic Seamline Mismatch (cm)
    X-cm X 1.41*X 2.45*X 2*X
     RMSEr = RMSEx 2 +RMSEy 2                     RMSEr =Radial RMSE=Circular RMSE=Twodimensional RMSE of X & Y 
  2. Aerial triangulation results should be twice as accurate as the generated products:
    1. Ortho and planimetric maps ONLY: RMSEx (AT) or RMSE(AT) = ½ * RMSEx(Map) or RMSEy(Map) and RMSEz(AT) = RMSEx(Map) or RMSEy(Map)  of orthoimagery
    2. For ortho, planimetric maps, and elevation maps:  RMSEx(AT) , RMSEy(AT)  or RMSEz(AT) = ½ * RMSEx(Map) , RMSEy(Map)  or RMSEz(DEM)
  3. Control points for aerial triangulation should be twice as accurate as aerial triangulation:
    1. For ortho and planimetric maps ONLY: RMSEx (GCPs) or RMSEy (GCPs) = 1/4 * RMSEx( Map ) or RMSEy( Map ) and RMSEz = 1/2 * RMSEx( Map ) or RMSEy( Map )
    2. For ortho/planimetric maps and elevation maps: RMSEx (GCPS) , RMSEy (GCPs) or RMSEz (GCPs) = 1/4 * RMSEx( Map ), RMSEy( Map ) or RMSEz( DEM )

Table 4 lists common horizontal accuracy classes for geospatial mapping products.

Table 4 Common horizontal accuracy classes for geospatial mapping products

Horizontal Accuracy Class RMSEx and RMSE(cm) RMSEr (cm) Orthoimage Mosaic Seamline Maximum Mismatch (cm) Horizontal Accuracy at the 95% Confidence Level (cm)
0.63 0.9 1.3 1.5
1.25 1.8 2.5 3.1
2.50 3.5 5.0 6.1
5.00 7.1 10.0 12.2
7.50 10.6 15.0 18.4
10.00 14.1 20.0 24.5
12.50 17.7 25.0 30.6
15.00 21.2 30.0 36.7
17.50 24.7 35.0 42.8
20.00 28.3 40.0 49.0
22.50 31.8 45.0 55.1
25.00 35.4 50.0 61.2
27.50 38.9 55.0 67.3
30.00 42.4 60.0 73.4
45.00 63.6 90.0 110.1
60.00 84.9 120.0 146.9
75.00 106.1 150.0 183.6
100.00 141.4 200.0 244.8
150.00 212.1 300.0 367.2
200.00 282.8 400.00 489.5
250.00 353.6 500.0 611.9
300.00 424.3 600.0 734.3
500.00 707.1 1000.0 1223.9
1000.00 1414.2 2000.0 2447.7