Crate wxy_domain 

wxy-domain

One data model for gridded, mesh and feature data, with no I/O and no CRS dependency. This is stage S1 of the wxylib roadmap; the design is in wxylib/design, documents 02 and 03.

The model separates three things that gridded-data software usually blurs (after Regular in what?, hypertidy/regular-in-what):

• index mapping: how a position follows from an index (Positions, one variant per rung of the Rung ladder);
• frame: what the positions mean (Frame, opaque to this crate);
• storage: what a producer wrote down. Readers record the stored form as given, and normalise turns it into a cheaper, equivalent mapping when the evidence allows, with a normalise::Report.

A Domain is index space (Dims) plus any number of Mappings, each covering some of the dims and naming its frame. A Field is values on a domain. A Collection groups fields and domains, and covers a classic raster dataset, a multidimensional group, a mesh with its datasets, or a feature layer.

Index space convention

Continuous index coordinates follow GDAL’s pixel convention: 0.0 is the outer edge of the first element along a dim and i + 0.5 is the centre of element i. Every mapping evaluates in this space, whatever its CellConvention says about where stored coordinates sit.

What is implemented in S1

Rungs R0 to R3 (index only, regular, rectilinear, curvilinear) are implemented and evaluate positions. R3’ (fitted models), R4 (implicit meshes such as DGGS) and R5/R6 (explicit meshes, features) are present as trait-object variants so the types will not change when they arrive.

Re-exports

pub use affine::Affine;

pub use collection::Collection;

pub use collection::Relation;

pub use collection::RelationKind;

pub use dim::Dim;

pub use domain::Domain;

pub use field::DataType;

pub use field::Field;

pub use field::Location;

pub use field::ValueSemantics;

pub use frame::Frame;

pub use mapping::CellConvention;

pub use mapping::Mapping;

pub use positions::CoordArray;

pub use positions::Positions;

pub use positions::Rung;

Modules

affine

Affine transforms in GDAL geotransform order.

collection

Collections: fields and domains together, with attributes.

dim

Dimensions: named axes of index space.

domain

Domains: index space plus the mappings that place it.

field

Fields: values on a domain.

frame

Frames: what the numbers a mapping produces mean.

mapping

Mappings: positions for some of a domain’s dims, in a named frame.

normalise

Normalisation: find a cheaper, equivalent mapping for what was stored.

positions

Positions: how a position follows from an index. One variant per rung.