[Requests] comment #4 on candidate OGC WMTS Simple Profile (OGC 13-082)

Keith Pomakis pomakis at cubewerx.com
Tue Jun 17 12:01:57 EDT 2014


1. Evaluator:
         Keith Pomakis <pomakis at cubewerx.com>
         CubeWerx Inc.
         815 boulevard de la Carrière, bureau 202
         Gatineau, Québec, Canada
         J8Y 6T4
         Tel: 819-771-8303, ext. 202

2. Submission: candidate OGC WMTS Simple Profile (OGC 13-082)


1. Requirement: General

2. Implementation Specification Section number: 7.6

3. Criticality: Editorial

4. Comments/justifications for changes:

It should be noted that because the proposed simple profile requires
servers to provide a global coverage of tiles, it cannot realistically
be used by file-system-only WMTS servers that serve only a small
high-resolution area.  That is, a file-system-only WMTS server (one
that consists only of a file system of pre-generated tiles with no
server process) that declares compliance to this simple profile would be
required to provide a global coverage of tiles even if the actual data
area is small.  The problem is compounded if the data is high resolution,
since high-resolution blank tiles for the rest of the world would need
to exist.

For example, it's trivial for a WMTS to serve high-resolution tiles of a
particular military base, and it's equally trivial for that WMTS server
to be file-system-only since it only needs to serve, say, 10,000 tiles,
which can all be pre-generated.  However, for this server to comply
to the simple profile, it would need to have over 23,456,247,900,000
pre-generated blank tiles (or an equal number of softlinks).

This is not necessarily a critical flaw in the simple profile, but I
think it should be noted as a limitation.

Keith Pomakis <pomakis at cubewerx.com>
Senior Software Developer, CubeWerx Inc.

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