This imaging time determination service is included under Image Coordinate Transformation Services because time can be considered to be another dimension of a point coordinate, or the
replacement for one axis of a point’s image coordinates. Furthermore, the data needed to determine imaging time is closely related to the data needed to convert image positions.
Specification and implementation of this imaging time determination service probably depends on specification of temporal reference systems. Imaging time determination also depends on the
temporal part of image geometry models. Complete specification of temporal reference systems has been put off for future work by the OGC. Therefore, complete specification and implementation of
this imaging time determination service may have to be delayed.
4.2.2. Service Subtypes
The one currently expected Imaging Time Determination Service is: 1.
Determine imaging times for one or more image positions
4.2.3. Result Data
The data produced by the Imaging Time Determination Service includes: 1.
Imaging time, for each point 2.
Metadata for imaging times, including: optional 3.
Temporal SRS definition is metadata for output times 4.
Absolute accuracy estimates for imaging times is metadata for output times
5. Relative accuracy estimates for imaging times
is metadata for output times Result metadata is optionally returned to client software, depending on how the service is called.
The ability to produce result metadata when requested is a required capability of the service.
4.2.4. Needed Data
The data needed for use by the Imaging Time Determination Service includes: 1.
Image position coordinates, for each point 2.
Output temporal SRS definition is metadata for output times 3.
Temporal SRS transformation parameters optional is metadata for temporal SRS or transformation
4. Temporal transformation accuracy estimates when output accuracy is needed is metadata
for temporal transformation 5.
Metadata for input position coordinates, including: 6.
Input SRS definition is metadata for input positions 7.
Absolute accuracy estimates for input position coordinates when output absolute accuracy is needed
is metadata for input positions 8.
Relative accuracy estimates for input position coordinates when output relative accuracy is needed is metadata for input positions
4.2.5. Discussion
The Temporal SRS transformation parameters item 3 in Section 4.2.4 must include or imply all the information needed to determine the imaging time for any point. For images collected over
some time, the Image coordinate transformation parameters item 3 in Section 4.1.4 must also imply or include all the information needed to determine the imaging time for any point. This
information may include the position interpolation algorithm to be used between discrete positions recorded along the sensor flight path, to determine intermediate positions or times. It is possible to
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record only discrete sensor positions, not a continuous record of the positions. In that case, an interpolation algorithm is needed to interpolate between the stored positions.
4.2.6. Object Model
TBD
Figure 3. Object Model of TBD
4.2.7. Class Name: TBD
Package Class Belongs to: Documentation:
Superclass: none Stereotype: none
Associations: Public Interface:
Attributes:
Operations:
Operation name: Return type:
Arguments: Documentation:
4.3. Image Geometry Model Conversion Services
