`geodetic_engine.persistablereference`¶

Reading and writing OSDU persistableReference definitions.

OSDU identifies the CRS, transformation or unit of a record with a persistableReference: a JSON envelope wrapping ESRI WKT, frequently URL-encoded, and found as the value of a field in another document – extract that string and pass it here as it is (a payload that has itself been JSON-encoded a second time is not decoded for you). It is self-contained, carrying the full definition rather than a code to look up, and this package reads it that way – the parameters are what is built from, and the authority code beside them is provenance.

Public entry points:

parse_persistable_reference() – read a payload into the reference it states.
CrsReference – a CRS, on its own or bound to a hub, with to_crs().
OperationReference – a transformation, single or concatenated, with to_operation().
UnitReference – a unit, with to_si() and from_si().
looks_like_reference() – whether a string is shaped like one, cheap enough to run on any CRS definition a caller passes in.

These hand back pyproj objects. from_persistable_reference() is the same thing wrapped in this package’s own CRS type, and transform() accepts a payload directly wherever it accepts a CRS.

A definition this package cannot translate exactly is refused. ESRI states several methods that differ from a supported one only by a convention or a term, so translating a near miss would give coordinates that look right and are metres out.

Example

>>> from geodetic_engine.persistablereference import parse_persistable_reference
>>> reference = parse_persistable_reference(payload)
>>> reference.authority_code
AuthorityCode(authority='OSDU', code='23032023')
>>> reference.to_crs().is_bound
True

Functions¶

`geogtran`	State one coordinate transformation as an ESRI `GEOGTRAN`.
`looks_like_reference`	Whether a string is shaped like a persistableReference.
`operation_from_geogtran`	Build the coordinate operation an ESRI `GEOGTRAN` states.
`parse_persistable_reference`	Read a persistableReference payload.
`to_persistable_reference`	Write a CRS or transformation as a persistableReference payload.

Classes¶

`AuthorityCode`	An authority and code naming one object.
`CrsReference`	A coordinate reference system, on its own or bound to a hub.
`Kind`	The kind of definition a persistableReference states.
`OperationReference`	A coordinate transformation, single or concatenated.
`Reference`	What every persistableReference states about itself.
`UnitReference`	A unit, stated by how it converts to its SI base.

Constants and type aliases¶

AnyReference

Exceptions¶

`MalformedReferenceError`	The payload is not a readable persistableReference.
`PersistableReferenceError`	Base class for every persistableReference failure.
`UnresolvableGridError`	A grid-based transformation names a dataset that resolves to no PROJ grid.
`UnsupportedMethodError`	A transformation states a method this package will not translate.
`UnsupportedReferenceError`	The payload is well formed but states a kind this package does not model.

Supporting types¶

Not exported from the subpackage, but returned or accepted by something that is.

`esriwkt.Node`	One bracketed element of an ESRI WKT definition.
`esriwkt.write`	Render an element back to ESRI WKT.