TOAST Graph storage

Graphs

The TOAST project is based on RDF graphs stored and manipulated via RDFLib https://github.com/RDFLib/rdflib.

Sources

The main LANDRS Ontology and instances are stored as Turtle files in the working repository https://github.com/landrs-toolkit/landrsOntTest. We are currently using the config branch for testing TOAST.

Configuration

The py_drone_graph_core.py Python file contains the graph initialization code configured via the [GRAPH] section in py_drone.ini.

[GRAPH]
name = landrs_test
db_location = db/${name}

#for Pricila's repo
file = ../landrsOntTest/
#sample file
#file = ttl/base.ttl

file_format = ttl
file_reload = False

# check created instances with pyshacl?
pyshacl = False

# shacl filenames
shacl_filename = *shape.${file_format}
shacl_constraint_filename = *shapes.${file_format}
flight_shacl_filename = ttl/

# ontology filename
ontology_filename = ontology.${file_format}

Storage

The graph interface code resides in the graph folder of the TOAST repository, utilizing the py_drone_graph class.

The graphs are stored in a SQLITE database named as db/landrs_test and contains the following graphs,

Main graphs

1. landrs_test, the main graph containing the ontology and instances from landrsOntTest. Internally named g1.
2. landrs_test_shape, the SHACL shapes from landrsOntTest. Internally named g2.

Configuration graphs

These graphs are populated from the shape files in /ttl. The graph name is defined by the filename up to the collective shape naming convention *shapes.${file_format}. So Flight_constraint_shapes.ttl -> Flight_constraint.

1. Drone_input, configuration shapes for the drone.
2. Flight_input, shapes that define the flight specific nodes to be created and the "graph boundaries" that require user input to resolve. Used to auto-generate the Flight input form.
3. Flight_constraint, shapes that define constraints for the "graph boundaries". For example the feature of interest must have an observable property and a sensor that can observe it.
4. Flight_store, shapes that define the nodes to be generated/updated during the flight. Includes the observation etc.
5. Sensor_parse, shapes that define the sensor.

All graphs can also be accessed via the Conjunctive graph internally named g.

Loading

If the SQLITE database does not exist then the files are re-loaded into a new database. The turtle files can be reloaded each time the code is run by setting file_reload = True.

PySHACL

Newly created instances can be rigorously checked against their SHACL files with PySHACL by setting pyshacl = True.