provide Open Imagery Network metadata for each map

[jywarren]

https://github.com/openimagerynetwork/metadata-spec/blob/master/sample.json

https://github.com/openimagerynetwork/metadata-spec

{
  "uuid" : "path/to/example.tif",
  "projection" : "PROJCS["NAD83 / Massachusetts Mainland", ...",
  "bbox" : [-180,-90,180,90],
  "footprint" : "POLYGON((-180 -90, -180 90, 180 90, 180 -90, -180 -90))",
  "gsd" : 0.35,
  "file_size" : 1024,
  "acquisition_start" : "2015-05-03T13:00:00.000",
  "acquisition_end" : "2015-05-04T13:00:00.000",
  "title" : "An scene from some satellite",
  "platform" : "satellite",
  "provider" : "Digital Globe",
  "contact" : "someone@nasa.gov",
  "properties" : {}
}

[jywarren]

So OIN's spec also requires HTTP content-range, which nginx 1.2.1 provides, but apparently whatever Rails is doing to serve files does not. We could set up a separate nginx instance to just serve static files, though.

[grvsachdeva]

Hey @jywarren, can you please add more details to this issue? Thanks!

[jywarren]

So this would require a new function in the maps_controller.rb which would output JSON in this format with all the information we're able to provide, at a route like https://mapknitter.org/maps/<map-slug>/metadata.json. But as we are transitioning potentially to image-centric listings instead of map-centric, would we want to quickly change this to display for each image, instead?

Under the new exporter, we may have a GeoTiff for each image, but even a JPG would be OK to report in this format. Some of the fields we'll need to research a bit more using the above link.