Provide tile cache proxy service from other sources

[cgiovando]

OAM Server could allow users creating a tile service using other services as input. This functionality would be useful in the case of a poor performing WMS which is cached either with a dynamic proxy or entirely pre-seeded. A couple of examples:

Some slow WMS --> OAM proxy --> OAM fast tile service
Some TMS in EPSG:4326 --> OAM proxy --> OAM EPSG:3857 tile service

Probably a feature for a future release, but something to consider, as from recent experience in the Nepal earthquake response, having this feature allows for more efficient imagery services.

We also need to consider whether is intended for OAM's scope creating tile services from non OIN sources.

[mojodna]

Fastly / Cloudfront / Cloudflare with long TTLs and configured for stale-while-revalidate would be a quick way to speed things up.

A later solution that would facilitate post-facto seeding could be a variant of #3's hybrid approach where an S3 bucket (possibly with a lifecycle policy that expires data after some time period) backs the CDN. Stamen uses tp to simultaneously proxy and populate the persistent cache.

What are some examples of EPSG:4326 TMSes?

We also need to consider whether is intended for OAM's scope creating tile services from non OIN sources.

My gut says no, but this could be part of HOT's mission more generally.