{"$schema":"https://proj.org/schemas/v0.7/projjson.schema.json","type":"GeodeticCRS","name":"ITRF91","datum":{"type":"DynamicGeodeticReferenceFrame","name":"International Terrestrial Reference Frame 1991","frame_reference_epoch":1988,"ellipsoid":{"name":"GRS 1980","semi_major_axis":6378137,"inverse_flattening":298.257222101}},"coordinate_system":{"subtype":"Cartesian","axis":[{"name":"Geocentric X","abbreviation":"X","direction":"geocentricX","unit":"metre"},{"name":"Geocentric Y","abbreviation":"Y","direction":"geocentricY","unit":"metre"},{"name":"Geocentric Z","abbreviation":"Z","direction":"geocentricZ","unit":"metre"}]},"scope":"Geodesy.","area":"World.","bbox":{"south_latitude":-90,"west_longitude":-180,"north_latitude":90,"east_longitude":180},"id":{"authority":"EPSG","code":4913},"remarks":"Replaces ITRF90 (code 4912). Replaced by ITRF92 (code 4914)."}