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 0.2.2 added a display API separate from network parsing. parse_display_bytes and parse_display_file return DisplayData::PowerWorld(PwdDisplay) for .pwd inputs. parse_file does not accept .pwd.

Reading .pwd

crates/tellegen-wasm/src/lib.rs exports parse_display(bytes, format) over powerio::parse_display_bytes. 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 pwd_mercator_to_lonlat; 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 0.7.1 ships the standalone geographic document (GeoLayer): 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 fills missing case coordinates through the SubNum join (geo_layer_from_pwd + apply_substation_points, projected by pwd_mercator_to_lonlat), and layouts computed by tellegen export with synthetic/manual provenance.