Copyright © 2012 Open Geospatial Consortium
81 b. If the time of acquisition of each frame is known and reasonably constant, even if the
request asks for a frame at an approximate time of acquisition or frame within a temporal range for an given bounding box AOI for a set of collections.
c. The specification could resolve any ambiguity in dereferencing a time value into an absolute frame number within a collection. For example, the specification may state: If
for a given collection, the requested time of acquisition T matches frame F
A
at time of acquisition T
A
and F
B
at time of acquisition T
B
because |T-T
A
| = |T-T
B
| then select F
A
, if F
A
F
B
. d. While this determination is completely arbitrary, it removes any ambiguity.
e. It could be made more complex by selecting F
A
or F
B
based on the context of the value of T. That is, for time ranges, select F
A
, if F
A
F
B
for start time of acquisition ambiguity resolution, and select F
B
, if F
A
F
B
for end time of acquisition ambiguity resolution. f. It is however recommended that time of acquisition to frame number ambiguity
resolution should be kept as simple as possible.
3.
A parameter named Metadata is introduced to include metadata in the response as part of a multipartRelated response content-type. The Disposition needs to be one of ‘ordered’ or
‘unordered’ for Metadata to be returned as part of a GetMap multipart request. It is generally useful for high latency environments. The implementation of this parameter is optional. The
Metadata parameter, if supported, shall be constrained to the allowed values of the GetCapabilities response.
24 IS service model
24.1 Summary
A summary of all the requests for an image service is specified in the table below:
Table 23: Image Service request summary
Request Meaning
Parameters Optionality
GetCapabilities Allows the client to retrieve metadata
about the capabilities of the IS server implementation
Service, Request, Sections, AcceptVersions, AcceptFormats,
AcceptLanguages, UpdateSequence
Mandatory
GetHelp Allows the client to retrieve help on topics
provided by the server Service, Request, Version, Topic,
Format Optional
GetMap Retrieves an area of interest from one or
more frames from one or more collections of WAMI data as one or more images or
images + metadata, in supported standard formats.
Service, Request, Version, Format, Accept Languages,
Disposition, CID, CRS, BBox, Width, Height, Styles,
Transparent, Bgcolor, Time, Metadata, Options
Mandatory
GetMapInfo The request is similar to the GetMap
request except that instead of images + metadata it retrieves metadata only.
Service, Request, Version, Format, Accept Languages, CID,
CRS, BBox, Width, Height, Optional
Copyright © 2012 Open Geospatial Consortium
82
Time, Metadata, Options GetPathMap
Retrieves areas of interest AOIs from one or more collections of WAMI data as
one or more images or images + metadata, in supported standard formats. The
information about the collection, time periods and bounding AOIs is supplied as
a path3.
Service, Request, Version, Format,
Accept Languages
, Disposition, CRS , Width, Height,
Styles, Transparent, Bgcolor , Metadata, Options, Path
Optional
GetPathMapInfo The request is similar to the GetPathMap
request except that instead of images + metadata it retrieves metadata only.
Service, Request, Version, Format,
Accept Languages
, CRS , Width, Height, Metadata,
Options, Path Optional
24.2 Request UML XMLKVP
Figure 13shows in detail the root XML elements representing all possible IS requests. All UML attributes represent XML and KVP request parameters, their data-type, and multiplicity.
There are complex element relationships which differ in the XML and KVP request encoding. See the specific request Parameter section to see KVP encoding for the following fields:
ViewPort Time
BBox Option
The ‘Path’ element relationship is retained as URL encoded XML for a ‘Path’ KVP parameter.
24.3 Collection Metadata UML XML
