Welcome to TFCat’s documentation!
The TFCat (Time-Frequency Catalogue) library is a utility to create and manage TFCat objects following the TFCat specification.
TFCat model is structured as follows:
TFCat Geometry — There are 7 types of TFCat Geometry: Point, MultiPoint, LineString, MultiLineString, Polygon, MultiPolygon, with an additional GeometryCollection, which is a set of any of the six other geometry types. Each geometry is composed of a set of coordinate pairs. A LineString is defined by a list of connected Point features, forming a continuous path. A Polygon is defined by a closed list of connected Point features, forming a closed contour. The feature type definitions are inspired from the GeoJSON specification.
TFCat Feature — A TFCat Feature contains one or several TFCat Geometries, and a set of properties, provided as a set of (key, value) pairs.
TFCat Field — A TFCat Field is defining the TFCat feature properties. Its minimal content includes a name, a description, a data type and a UCD (Unified Content Descriptors). It may also include a unit (following the VOUnit –Virtual Observatory Unit– specification), or a set of allowed values, when applicable.
TFCat Property — A TFCat Property is a (key, value) pair. When used in a TFCat feature, the properties must be defined as a TFCat Field. When used at the main TFCat level, it should provide generic information on the catalogue, such as: title, authors, reference, instrument, etc.
TFCat Coordinate Reference System — A TFCat Coordination Reference System (CRS) contains a description of the time axis, a description of the spectral axis, and a reference position. The TFCat CRS could be of three types: name, link or local. Note that the local type is the only one supported in this version.
Current version and namespace
The current TFCat supported specification version is 1.0. The corresponding TFCat JSON Schema URI is: https://voparis-ns.obspm.fr/maser/tfcat/v1.0/schema#