Improve support for online COG about localtileserver

[banesullivan]

Aha, so you're bringing up something that I wanted to make clear with the name. localtileserver is intended to be used only to serve tiles from raster files that exist on your local filesystem. If you want a tile server that can handle accessing remote files, you have a few options:

1. We create a new remotetileserver package or submodule here
2. You can use Resonant GeoData (which my team and I at Kitware have put a TON of work into handling tile serving from cloud-hosted data). See ResonantGeoData/ResonantGeoData#603 for a demonstration.
3. You can use GDAL's Virtual Storage Interface since we're using large_image which is simply wrapping GDAL for data access.

In your particular case, this should work because your raster is a pre-tiled Cloud Optimized GeoTiff. I have this working locally with minimal changes to localtileserver I will push the change to a PR for you to test soon

[giswqs]

Resonant GeoData seems awesome. I need to look into it. It would be great if you can make localtileserver work for pre-tiled COG. It might be too much work to create and maintain another package like remotetileserver.

[banesullivan]

It might be too much work to create and maintain another package like remotetileserver.

Well that is what Resonant GeoData is.... 😉