newline-delimited GeoJSON writer

python/core/python/geoarrow/rust/core/_rust.pyi

@@ -1239,20 +1239,20 @@ def read_csv(
     batch_size: int = 65536,
 ) -> GeoTable: ...
 def read_flatgeobuf(
-    file: Union[str, Path, BinaryIO], batch_size: int = 65536
+    file: Union[str, Path, BinaryIO], *, batch_size: int = 65536
 ) -> GeoTable: ...
 async def read_flatgeobuf_async(
     url: str, *, batch_size: int = 65536, options: Dict[str, str] | None = None
 ) -> GeoTable: ...
 def read_geojson(
-    file: Union[str, Path, BinaryIO], batch_size: int = 65536
+    file: Union[str, Path, BinaryIO], *, batch_size: int = 65536
 ) -> GeoTable: ...
 def read_geojson_lines(
-    file: Union[str, Path, BinaryIO], batch_size: int = 65536
+    file: Union[str, Path, BinaryIO], *, batch_size: int = 65536
 ) -> GeoTable: ...
 def read_ipc(file: Union[str, Path, BinaryIO]) -> GeoTable: ...
 def read_ipc_stream(file: Union[str, Path, BinaryIO]) -> GeoTable: ...
-def read_parquet(path: str, batch_size: int = 65536) -> GeoTable: ...
+def read_parquet(path: str, *, batch_size: int = 65536) -> GeoTable: ...
 def read_postgis(connection_url: str, sql: str) -> Optional[GeoTable]: ...
 async def read_postgis_async(connection_url: str, sql: str) -> Optional[GeoTable]: ...
 def read_pyogrio(
@@ -1284,6 +1284,9 @@ def write_flatgeobuf(
 def write_geojson(
     table: ArrowStreamExportable, file: Union[str, Path, BinaryIO]
 ) -> None: ...
+def write_geojson_lines(
+    table: ArrowStreamExportable, file: Union[str, Path, BinaryIO]
+) -> None: ...
 def write_ipc(
     table: ArrowStreamExportable, file: Union[str, Path, BinaryIO]
 ) -> None: ...

python/core/src/io/geojson_lines.rs

@@ -1,10 +1,11 @@
 use crate::error::PyGeoArrowResult;
-use crate::io::file::BinaryFileReader;
+use crate::io::file::{BinaryFileReader, BinaryFileWriter};
 use crate::table::GeoTable;
 use geoarrow::io::geojson_lines::read_geojson_lines as _read_geojson_lines;
+use geoarrow::io::geojson_lines::write_geojson_lines as _write_geojson_lines;
 use pyo3::prelude::*;
 
-/// Read a GeoJSON Lines file from a path on disk into a GeoTable.
+/// Read a newline-delimited GeoJSON file from a path on disk into a GeoTable.
 ///
 /// This expects a GeoJSON Feature on each line of a text file, with a newline character separating
 /// each Feature.
@@ -25,3 +26,25 @@ pub fn read_geojson_lines(
     let table = _read_geojson_lines(&mut reader, Some(batch_size))?;
     Ok(GeoTable(table))
 }
+
+/// Write a GeoTable to a newline-delimited GeoJSON file on disk.
+///
+/// Note that the GeoJSON specification mandates coordinates to be in the WGS84 (EPSG:4326)
+/// coordinate system, but this function will not automatically reproject into WGS84 for you.
+///
+/// Args:
+///     table: the table to write.
+///     file: the path to the file or a Python file object in binary write mode.
+///
+/// Returns:
+///     None
+#[pyfunction]
+pub fn write_geojson_lines(
+    py: Python,
+    mut table: GeoTable,
+    file: PyObject,
+) -> PyGeoArrowResult<()> {
+    let writer = file.extract::<BinaryFileWriter>(py)?;
+    _write_geojson_lines(&mut table.0, writer)?;
+    Ok(())
+}

python/core/src/lib.rs

@@ -184,6 +184,10 @@ fn _rust(_py: Python, m: &PyModule) -> PyResult<()> {
         m
     )?)?;
     m.add_function(wrap_pyfunction!(crate::io::geojson::write_geojson, m)?)?;
+    m.add_function(wrap_pyfunction!(
+        crate::io::geojson_lines::write_geojson_lines,
+        m
+    )?)?;
 
     // Interop
     m.add_function(wrap_pyfunction!(

python/docs/source/api/core/io.md

@@ -21,6 +21,7 @@ Read and write to files on disk and databases like PostGIS.
         - write_csv
         - write_flatgeobuf
         - write_geojson
+        - write_geojson_lines
         - write_ipc
         - write_ipc_stream
         - write_parquet

src/io/geojson_lines/mod.rs

@@ -1,5 +1,7 @@
-//! Read from [newline-delimited GeoJSON](https://stevage.github.io/ndgeojson/) files.
+//! Read from and write to [newline-delimited GeoJSON](https://stevage.github.io/ndgeojson/) files.
 
 mod reader;
+mod writer;
 
 pub use reader::read_geojson_lines;
+pub use writer::write_geojson_lines;

src/io/geojson_lines/writer.rs

@@ -0,0 +1,13 @@
+use geozero::geojson::GeoJsonLineWriter;
+use geozero::GeozeroDatasource;
+use std::io::Write;
+
+use crate::error::Result;
+use crate::table::GeoTable;
+
+/// Write a table to newline-delimited GeoJSON
+pub fn write_geojson_lines<W: Write>(table: &mut GeoTable, writer: W) -> Result<()> {
+    let mut geojson_writer = GeoJsonLineWriter::new(writer);
+    table.process(&mut geojson_writer)?;
+    Ok(())
+}