InSAR fields¶

The following properties are exposed by InsarExtension for Items, Assets, and item asset definitions. Values are stored in Item properties, Asset extra_fields, or the item asset definition's properties dictionary.

STAC field	Python property	Meaning and setter behavior
insar:perpendicular_baseline	perpendicular_baseline	Perpendicular baseline in meters; accepts integers and floats and stores a float.
insar:temporal_baseline	temporal_baseline	Temporal baseline in days; accepts integers and floats and stores a float.
insar:height_of_ambiguity	height_of_ambiguity	Height of ambiguity in meters; accepts integers and floats and stores a float.
insar:reference_datetime	reference_datetime	Reference acquisition datetime; accepts a Python datetime and stores a string.
insar:secondary_datetime	secondary_datetime	Secondary acquisition datetime; accepts a Python datetime and stores a string.
insar:processing_dem	processing_dem	DEM used during interferogram processing; accepts a string.
insar:geocoding_dem	geocoding_dem	DEM used during geocoding; accepts a string.

Every getter can return None for an absent field. Every setter accepts None to remove its field. apply() defaults all arguments to None, so omitted values are removed rather than preserved.

Runtime checks¶

Numeric setters reject booleans and nonnumeric values with ValueError. They do not enforce ranges, finiteness, or consistency with acquisition dates. DEM setters reject non-string values with ValueError; they do not check whether a DEM identifier exists or a URL is reachable, and they accept empty strings.

Datetime getters parse stored strings using PySTAC's datetime utilities. Use timezone-aware Python datetimes when writing acquisition times. Reading existing metadata does not run the setter checks again.

Collection summaries¶

InsarExtension.summaries(collection) exposes these properties:

Python property	Stored summary
reference_datetime	Single-element list containing a datetime string.
processing_dem	Single-element list containing a DEM string.
geocoding_dem	Single-element list containing a DEM string.

Summary getters return the first element, or None when no list is available or the list is empty. Reference datetimes are parsed to Python datetimes. A non-string first element raises ValueError, except that a first element of None is returned as None.

Setters replace the entire list with a single-element list. Assigning None removes the summary. The helper does not expose baseline, height-of-ambiguity, or secondary-datetime summaries, and does not aggregate Item values automatically.