What is the scope of stac-validator?

[philvarner]

We have stac-validator and stac-check, which do different things.

stac-check explicitly states the scope of what it does as:

The intent of this project is to provide a validation tool that also follows the official
[STAC Best Practices document](https://github.com/radiantearth/stac-spec/blob/master/best-practices.md)

but stac-validator doesn't. Currently, I think stac-validator only validates the STAC json against the JSON Schemas, which is a useful module to have, since the STAC Extensions make constructing the entire JSON Schema not as simple as it could be. Because of this, I think stac-validator should explicitly state that it only does schema validation, and that the project be restricted to only that behavior.

Then the issue is with other syntactic and semantic validations that fall in between stac-validator and the current definition of stac-check of only being for Best Practices, for example:

• a bbox that's supposed to cross the antimeridian doesn't have inverted longitude points and belt the globe instead
• a polygon doesn't have it's positions reversed (lat, lon) instead of (lon, lat), e.g., lat is outside -90/90
• polygons are wound correctly
• polygons are split instead of crossing the antimeridian
• proj:centroid doesnt' have the lat and lon attributes reversed

Exapanding the scope of stac-check to include things like this is the apparent solution, and probably also adding the ability to suppress various warnings (if that doesn't already exist?).

[jonhealy1]

Some great feedback here @philvarner. These would be good additions to stac-check I think.

[philvarner]

One other question I had was the difference between this package and https://pystac.readthedocs.io/en/stable/api/validation.html is? I didn't know about that one until recently.