JSON Schema draft-07

[mojodna]

This updates the JSON schemas to draft-07.

From http://json-schema.org/draft-07/json-schema-release-notes.html:

For the Core and Validation specifications, draft-07 is a relatively minor update. In terms of validation keywords and outcomes, it is fully backwards-compatible with draft-06.

GeoJSON Features are directly addressable (for validators that resolve external URLs). I think stac-validator will handle this, but can't check due to stac-utils/stac-validator#27.

I've got this working with ajv (which is where the id → $id change was recommended) in STAC Browser (it validates behind the scenes and logs warnings to the JS console):

radiantearth/stac-browser@5b42b6b

loadSchema was what was needed there to resolve remote schema $refs (and why it didn't work using ajv-cli on the command line).

[mojodna]

@jbants does this work with STAClint?

[mojodna]

@brianbancroft looks like this might be up your alley?

[jbants]

Hey @mojodna, im out travelling in India until mid January. Brian is going to have a look. Off the top of my head I think the JSON spec library we are using supports 7. But we will test it out to confirm

[brianbancroft]

Hello @mojodna and @jbants, and sorry for the delayed response. I confirm that the json spec library used by Sparkgeo's library does support draft 7 out of the box.

The following are the relevant docs on the library which we use:

https://python-jsonschema.readthedocs.io/en/latest/validate/#jsonschema.Draft4Validator

[m-mohr]

This change will let the JavaScript Validator fail for mostly all requests (can't resolve external references), so we should remove the instructions for it with this PR, too.

[mojodna]

Good call. I'll take that on soon.

[m-mohr]

This needs some work.

1. Resolving conflicts
2. Updating recently added schemes to also follow draft 7, such as the SAR JSON schema in #393
3. Remove the JS (ajv) validation from the README

[cholmes]

Looks good.