Display Data

Case files and display files are separate inputs. MATPOWER .m, PSS/E .raw, and PowerWorld .aux files describe the network. JSON files are accepted as geographic files in this release. PowerWorld .pwd files describe a one-line diagram. tellegen reads coordinates from case files when they exist and reads diagram positions from display files when they are dropped.

PowerIO 0.11 routes display data through its universal parser. A .pwd source passed to powerio::parse returns a generation-2 PioModule whose value is a PioValue::GeoLayer; the older parse_display, parse_display_file, and DisplayData::PowerWorld(PwdDisplay) integration surface no longer exists.

Reading .pwd

crates/tellegen-wasm/src/lib.rs retains its browser-facing parse_display(bytes, format) wrapper, but implements it with the universal powerio::parse entry point and narrows the returned module to GeoLayer. The frontend reads .pwd files with arrayBuffer() and passes a Uint8Array to the WebAssembly module.

A dropped .pwd creates a local display entry with substation points only. It does not create buses, branches, or a solvable case.

Projecting .pwd coordinates

PowerWorld .pwd coordinates are diagram coordinates, not latitude and longitude. TAMU-generated diagrams use Web Mercator scaled by one constant, K = 535.81608, with both axes expressed in degrees:

x = K * lon
y = K * mercdeg(lat)
mercdeg(lat) = (180 / pi) * ln(tan(pi / 4 + lat * pi / 360))

The inverse transform is PowerIO’s to_lonlat_from_pwd_mercator; the wasm parse_display export returns each substation with its projected lon/lat alongside the raw diagram coordinates, so the frontend never reimplements the constant. This places checked ACTIVSg diagrams within about 0.02 degrees of their corresponding named cities. Hand-edited diagrams can differ, so tellegen labels these positions as approximate.

The canonical geographic document

PowerIO’s standalone geographic document (GeoLayer) carries element points and branch routes in one coordinate space, keyed by uid, external id, name, or the branch endpoint pair, written as a GeoJSON FeatureCollection with the powerio_geo foreign member (.geo.json). tellegen consumes it rather than defining a separate format: dropped geographic sidecars parse through its tolerant reader, applied coordinates land on the network (Bus.location, Branch.route), and the case panel exports the current layout as a .geo.json layer with provenance stamped.

On top of it, a dropped .pwd sibling already parses to GeoLayer and fills missing case coordinates through the SubNum join (apply_substation_points, projected by to_lonlat_from_pwd_mercator), and layouts computed by tellegen export with synthetic/manual provenance.