search

radiantearth / stac-spec

SpatioTemporal Asset Catalog specification - making geospatial assets openly searchable and crawlable
https://stacspec.org
Apache License 2.0
777 stars 178 forks source link

BBOX definition #1154

Closed mrepse closed 4 months ago

mrepse commented 3 years ago

I have a short question regarding STAC metadata. What exactly is the definition of the BBOX field (https://github.com/radiantearth/stac-spec/blob/master/item-spec/item-spec.md#item-fields) assuming the footprint is known? There are two ways of interpreting the text and we aren't sure what exactly is meant here.

  1. stac bbox = bbox(stac geometry)
  2. stac bbox = bbox(tiff file bbox reprojected to wgs84)

2 is always larger than (or equal to) 1. Would appreciate some clarification.

thanks

m-mohr commented 3 years ago

My understanding is that it's option 1 as it's GeoJSON, which implies that the GeoJSON bbox is computed from the GeoJSON geometry and they have to relate to each other.

For the original bbox/geometry/projection of the tiff file you'd use the proj extension: https://github.com/stac-extensions/projection/#item-properties-or-asset-fields

PowerChell commented 4 months ago

Closing due to updated language in item-spec bbox definition