Crate energyml_export 

Writing EnergyML geometry out to formats other programs read.

A registry, because the list is never finished

OBJ, GeoJSON and VTK - in three flavours - are here. glTF, PLY, shapefiles and whatever a particular site needs are not, and hard-coding a match over format names would mean every one of them is a change to this crate. So an exporter is a Exporter implementation in a Exporters registry, exactly as an array backend and a representation reader are:

let mut exporters = Exporters::builtin();
exporters.push(mine);              // found before the built-ins

An application adds a format without touching this crate, and a format added here reaches every caller - including the energyml export command, which lists whatever the registry holds rather than a list of its own.

Metadata is configuration, not code

What each format carries beyond the geometry is an energyml_domain::metadata::Spec - a JSON file of key → dotted path, where a path may cross references into other objects:

{
  "uuid":    "uuid",
  "title":   "Citation.Title",
  "type":    "contentType",
  "feature": "RepresentedInterpretation.InterpretedFeature.Citation.Title"
}

One spec, every format: the same keys come out as GeoJSON properties, VTK FieldData arrays and OBJ comments. Adding a key is editing a file, not editing this crate - which is the same argument as the registry, one level down.

What an exporter is given

A SceneObject: the shape, the coordinate system, and the identity - uuid, ETP URI, title, and the interpretation and feature above it. The last part matters more than it looks. An exported surface that is only triangles cannot be traced back to what it represents, and tracing back is usually the reason for exporting.

Where the coordinates end up

Each exporter states the Placement it wants, and gets it. OBJ asks for metres, because a mesh viewer wants numbers near the origin in a single unit. GeoJSON asks for metres and then needs degrees, which is a datum transformation and not arithmetic - so it goes through energyml_domain::reproject, and refuses rather than writing projected metres into a field the format says is longitude. That refusal is the honest answer: a GeoJSON with eastings in the longitude column loads fine and puts the model in the Gulf of Guinea.

Re-exports

pub use error::Error;

pub use error::Result;

pub use registry::Exporter;

pub use registry::Exporters;

pub use registry::Options;

pub use shapes::Selector;

pub use shapes::Shapes;

Modules

csv

Long CSV - one row per (object, element, property), in metres.

error

What can go wrong writing geometry out.

geojson

GeoJSON - features in WGS 84, carrying their identity.

obj

Wavefront OBJ - triangles and polylines, in metres.

registry

The exporter trait and the registry that holds them.

shapes

Choosing, per type, what form an export should take.

vtk

VTK, in the three flavours a caller is likely to be asked for.