georust / wkt

Rust read/write support for well-known text (WKT)
https://crates.io/crates/wkt
Apache License 2.0
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API to infer only geometry type/dimension #117

Open kylebarron opened 8 hours ago

kylebarron commented 8 hours ago

In cases like GeoArrow, it's nice to know if all input geometries have a common geometry type.

This would mean an API like

pub enum GeometryType {
    Point,
    LineString,
    ...,
    PointZ,
    PointM,
    PointZM,
}

and then

pub fn infer_type(wkt: &str) -> GeometryType {}

infer_type would only parse up to the first ( character, using that text to infer the geometry type and dimension.

There's a tradeoff between time spent first parsing the text to get the geometry types and then again to actually parse the geometries, vs memory overhead of parsing all objects first to Wkt objects and then inferring what type of array builder to use.

But I figure that scanning a string for the first instance of ( and matching those first characters should be very fast, especially if no numeric parsing needs to happen for that first stage.

Thoughts?

kylebarron commented 8 hours ago

For reference, in geoarrow-rs we plan to use the wkt crate directly for reading/writing WKT instead of using the geozero wrapper. See https://github.com/geoarrow/geoarrow-rs/issues/790, https://github.com/geoarrow/geoarrow-rs/issues/762