Function Metadata Access Services

3.8. Accuracy Conversion Services

3.8.1. Function

The Accuracy Conversion Services convert position accuracy estimates between error covariance matrix form and Circular Error CE plus Linear Error LE or other forms. These accuracy conversions are also applicable to linear dimensions and perhaps other accuracy estimates.

3.8.2. Service Subtypes

Services in this category include, but are not limited to, the following: 3.8.2.1. Convert covariance matrices to other forms 3.8.2.1.1. Convert 3-D covariances to CE plus LE 3.8.2.1.2. Convert 2-D covariances to CE 3.8.2.1.3. Convert 1-D variance to LE 3.8.2.1.4. Convert 1-D variance to Standard Deviation 3.8.2.1.5. Convert 3-D covariances to Spherical Error 3.8.2.2. Convert other forms to covariance matrices 3.8.2.2.1. Convert CE plus LE to 3-D covariances 3.8.2.2.2. Convert CE to 2-D covariances 3.8.2.2.3. Convert LE to 1-D variance 3.8.2.2.4. Convert Standard Deviation to 1-D variance 3.8.2.2.5. Convert Spherical Error to 3-D covariances

3.8.3. Results Data

The data resulting from these services output data includes, but are not limited to: 1. Accuracy estimates in desired form is metadata for some point positions 2. Confidence levels for output CE and LE values is metadata for CE and LE values?

3.8.4. Needed data

Inputs needed data to these services include, but are not limited to, the following: 1. Accuracy estimates in another form is metadata for same point positions 2. Selection of accuracy estimate form desired 3. Confidence levels for input CE and LE values is metadata for CE and LE values? 4. Accuracy conversion parameters is metadata for accuracy conversions?

3.8.5. Discussion

Both absolute and relative accuracy estimates can be separately converted by these services. Some cells of a covariance matrix may be unknown, and unknown cells must be handled in an appropriate manner. When converting most other forms of accuracy data to covariance matrices, correct values will not be known for some covariance matrix cells. Specifically, the off-diagonal cells for covariances between coordinates will not be known. As specified in Abstract Specification Topic 9: Quality, the values of these covariance matrix cells should be null or missing. Alternately, these covariances values would be assumed to be zero.

3.9. Metadata Access Services

3.9.1. Function

The Open GIS Abstract Specification Page 40 Volume 15: Image Exploitation Services 00-115 corrigendum The Metadata Access Services retrieve or modify desired metadata, converting its format when needed.

3.9.2. Service Subtypes