Module org.opengis.geoapi
Package org.opengis.metadata.quality

Interface AbsoluteExternalPositionalAccuracy

All Superinterfaces:
Element, PositionalAccuracy
@UML(identifier="DQ_AbsoluteExternalPositionalAccuracy", specification=ISO_19157) public interface AbsoluteExternalPositionalAccuracy extends PositionalAccuracy
Closeness of reported coordinate values to values accepted as being true. Can be used for the following measurement types (non-exhaustive list):
  • Data quality measures for positional uncertainty in general.
  • Height measurements as position observations in one dimension. The height may therefore be treated as a one-dimensional random variable.
  • Horizontal point locations are defined by a 2D coordinates. The uncertainty of any point location can be described using the data quality basic measures for 2D random variables.

Standardized values

In order to achieve well defined and comparable quality information, it is recommended to report data quality using quality measures listed in ISO 19157 annex. The following table provides a summary adapted to GeoAPI objects; see ISO 19157 for more complete descriptions and formulas. All identifiers should be in "ISO 19157" namespace.
Standardized values derived from ISO 19157
Identifier Name of measure Aliases Basic measure Parameters Value type
28 mean value of positional uncertainties (1D, 2D and 3D) Quantity
128 bias of positions (1D, 2D and 3D) Quantity
29 mean value of positional uncertainties excluding outliers (2D) emax Quantity
30 number of positional uncertainties above a given threshold error count emax Quantity
31 rate of positional uncertainties above a given threshold emax Quantity
32 covariance matrix variance-covariance matrix Matrix
33 linear error probable LEP LE50 or LE50(r) Quantity
34 standard linear error SLE LE68.3 or LE68.3(r) Quantity
35 linear map accuracy at 90% significance level LMAS 90% LE90 or LE90(r) Quantity
36 linear map accuracy at 95% significance level LMAS 95% LE95 or LE95(r) Quantity
37 linear map accuracy at 99% significance level LMAS 99% LE99 or LE99(r) Quantity
38 near certainty linear error LE99.8 or LE99.8(r) Quantity
39 root mean square error RMS Quantity
40 absolute linear error at 90% significance level of biased vertical data LMAS Quantity
41 absolute linear error at 90% significance level of biased vertical data ALE Sample size Quantity
42 circular standard deviation Helmert's point error, CSE CE39.4 Quantity
43 circular error probable CEP CE50 Quantity
44 circular error at 90% significant level circular map accuracy standard CE90 Quantity
45 circular error at 95% significant level navigation accuracy CE95 Quantity
46 circular near certainty error CNCE CE99.8 Quantity
47 root mean square error of planimetry RMSEP Quantity
48 absolute circular error at 90% significance level of biased data CMAS Quantity
49 absolute circular error at 90% significance level of biased data ACE Sample size Quantity
50 uncertainty ellipse standard point error ellipse (a, b, φ)
51 confidence ellipse confidence point error ellipse significance level (a, b, φ)

Note: ISO 19157 declares the covariance matrix value type as "Measure" associated with ValueStructure.MATRIX. For an object oriented language like Java, a more natural approach is to use an object of specific type for the value.

Definitions:

  1. Mean value of the distance between a measured position and what is considered as the corresponding true position.
  2. Deviation between a measured position and what is considered as the corresponding true position.
  3. For a set of points where the distance does not exceed a defined threshold, the arithmetical average of distances between their measured positions and what is considered as the corresponding true positions.
  4. Number of positional uncertainties above a given threshold for a set of positions. The errors are defined as the distance between a measured position and what is considered as the corresponding true position.
  5. Number of positional uncertainties above a given threshold for a set of positions in relation to the total number of measured positions. The errors are defined as the distance between a measured position and what is considered as the corresponding true position.
  6. Symmetrical square matrix with variances of point coordinates on the main diagonal and covariance between these coordinates as off-diagonal elements.
  7. Half length of the interval defined by an upper and a lower limit, in which the true value lies with probability 50%.
  8. Half length of the interval defined by an upper and a lower limit, in which the true value lies with probability 68.3%.
  9. Half length of the interval defined by an upper and a lower limit, in which the true value lies with probability 90%.
  10. Half length of the interval defined by an upper and a lower limit, in which the true value lies with probability 95%.
  11. Half length of the interval defined by an upper and a lower limit, in which the true value lies with probability 99%.
  12. Half length of the interval defined by an upper and a lower limit, in which the true value lies with probability 99.8%.
  13. Linear root mean square error.
  14. Absolute vertical accuracy of the data’s coordinates, expressed in terms of linear error at 90% probability given that a bias is present.
  15. Absolute vertical accuracy of the data’s coordinates, expressed in terms of linear error at 90% probability given that a bias is present.
  16. Radius describing a circle, in which the true point location lies with the probability of 39.4%.
  17. Radius describing a circle, in which the true point location lies with the probability of 50%.
  18. Radius describing a circle, in which the true point location lies with the probability of 90%.
  19. Radius describing a circle, in which the true point location lies with the probability of 95%.
  20. Radius describing a circle, in which the true point location lies with the probability of 99.8%.
  21. Radius of a circle around the given point, in which the true value lies with probability P.
  22. Absolute horizontal accuracy of the data’s coordinates, expressed in terms of circular error at 90% probability given that a bias is present.
  23. Absolute horizontal accuracy of the data’s coordinates, expressed in terms of circular error at 90% probability given that a bias is present.
  24. 2D ellipse with the two main axes indicating the direction and magnitude of the highest and the lowest uncertainty of a 2D point.
  25. 2D ellipse with the two main axes indicating the direction and magnitude of the highest and the lowest uncertainty of a 2D point.
Since:
2.0