geoarrow-schema 0.8.0

use serde::{Deserialize, Serialize};

/// The edge interpretation between explicitly defined vertices.
///
/// This does not affect format conversions (e.g., parsing `geoarrow.wkb` as
/// `geoarrow.linestring`), but does affect distance, intersection, bounding, overlay, length, and
/// area calculations. The `edges` key must be omitted to indicate planar/linear edges or be one
/// of:
///
/// If the `edges` key is omitted, edges will be interpreted following the language of
/// [Simple features access](https://www.opengeospatial.org/standards/sfa):
///
/// > **simple feature** feature with all geometric attributes described piecewise
/// > by straight line or planar interpolation between sets of points (Section 4.19).
///
/// If an implementation only has support for a single edge interpretation (e.g.,
/// a library with only planar edge support), an array with a different edge type
/// may be imported without losing information if the geometries in the array
/// do not contain edges (e.g., `geoarrow.point`, `geoarrow.multipoint`, a
/// `geoarrow.wkb`/`geoarrow.wkt` that only contains points and multipoints, or any
/// array that only contains empty geometries). For arrays that contain edges,
/// the error introduced by ignoring the original edge interpretation is similar to
/// the error introduced by applying a coordinate transformation to vertices (which
/// is usually small but may be large or create invalid geometries, particularly if
/// vertices are not closely spaced). Ignoring the original edge interpretation will
/// silently introduce invalid and/or misinterpreted geometries for any edge that crosses
/// the antimeridian (i.e., longitude 180/-180) when translating from non-planar
/// to planar edges.
///
/// Implementations may implicitly import arrays with an unsupported edge type if the
/// arrays do not contain edges. Implementations may otherwise import arrays with an
/// unsupported edge type with an explicit opt-in from a user or if accompanied
/// by a prominent warning.
#[derive(Debug, Clone, Copy, Serialize, Deserialize, PartialEq, Eq, Hash)]
pub enum Edges {
    /// Edges in the longitude-latitude dimensions follow a path calculated by
    /// the fomula in Thomas, Paul D. Mathematical models for navigation systems. US Naval
    /// Oceanographic Office, 1965 using the ellipsoid specified by the `"crs"`.
    #[serde(rename = "andoyer")]
    Andoyer,

    /// Edges in the longitude-latitude dimensions follow a path calculated by the fomula in
    /// [Karney, Charles FF. "Algorithms for geodesics." Journal of Geodesy 87 (2013):
    /// 43-55](https://link.springer.com/content/pdf/10.1007/s00190-012-0578-z.pdf) and
    /// [GeographicLib](https://geographiclib.sourceforge.io/) using the ellipsoid specified by the
    /// `"crs"`. GeographicLib available via modern versions of PROJ.
    #[serde(rename = "karney")]
    Karney,

    /// Edges in the longitude-latitude dimensions follow the
    /// shortest distance between vertices approximated as the shortest distance
    /// between the vertices on a perfect sphere. This edge interpretation is used by
    /// [BigQuery Geography](https://cloud.google.com/bigquery/docs/geospatial-data#coordinate_systems_and_edges),
    /// and [Snowflake Geography](https://docs.snowflake.com/en/sql-reference/data-types-geospatial).
    ///
    /// A common library for interpreting edges in this way is
    /// [Google's s2geometry](https://github.com/google/s2geometry); a common formula
    /// for calculating distances along this trajectory is the
    /// [Haversine Formula](https://en.wikipedia.org/wiki/Haversine_formula).
    #[serde(rename = "spherical")]
    Spherical,

    /// Edges in the longitude-latitude dimensions follow a path calculated by
    /// the fomula in Thomas, Paul D. Spheroidal geodesics, reference systems, & local geometry.
    /// US Naval Oceanographic Office, 1970 using the ellipsoid specified by the `"crs"`.
    #[serde(rename = "thomas")]
    Thomas,

    /// Edges in the longitude-latitude dimensions follow a path calculated
    /// using [Vincenty's formula](https://en.wikipedia.org/wiki/Vincenty%27s_formulae) and
    /// the ellipsoid specified by the `"crs"`.
    #[serde(rename = "vincenty")]
    Vincenty,
}