Lib.rs

将GDAL兼容的地理空间数据读写到 Polars 和 GeoPolars。

支持将以下地理空间格式读写到/从Polars DataFrame中

1. GeoJSON
2. ShapeFiles
3. 带有经纬度的CSV
4. FlatGeobuf
5. KML
6. GPX
7. PostGIS（通过网络）
8. SpatialLite
9. ... 以及 许多更多

示例1：来自文件的DataFrame

use polars_gdal::df_from_resource;
let df = df_from_resource("my_shapefile.shp", None).unwrap();
println!("{}", df);

示例2：来自原始字节的DataFrame

use polars_gdal::df_from_bytes;

let geojson = r#"{"type":"FeatureCollection","features":[{"type":"Feature","properties":{"name":"foo"},"geometry":{"type":"Point","coordinates":[1,2]}},{"type":"Feature","properties":{"name":"bar"},"geometry":{"type":"Point","coordinates":[3,4]}}]}"#.as_bytes();

let df = df_from_bytes(geojson, None, None).unwrap();
println!("{}", df);

示例3：来自GDAL层的DataFrame，带有过滤查询

use polars_gdal::{df_from_layer, gdal};
use gdal::vector::sql;

let dataset = gdal::Dataset::open("my_shapefile.shp")?;
let query = "SELECT kind, is_bridge, highway FROM my_shapefile WHERE highway = 'pedestrian'";
let mut result_set = dataset.execute_sql(query, None, sql::Dialect::DEFAULT).unwrap().unwrap();

let df = df_from_layer(&mut result_set, None).unwrap();
println!("{}", df);

示例4：来自具有自定义解析选项的经纬度CSV的DataFrame

let mut params = polars_gdal::Params::default();
let csv_parsing_options = ["EMPTY_STRING_AS_NULL=YES", "KEEP_GEOM_COLUMNS=NO", "X_POSSIBLE_NAMES=Lon*", "Y_POSSIBLE_NAMES=Lat*"];
params.open_options = Some(&csv_parsing_options);
 
let df = df_from_resource("lat_lon_countries.csv", Some(params)).unwrap();
println!("{}", df);

示例5：来自PostGIS表的DataFrame

use polars_gdal::{df_from_resource, Params};

let mut params = Params::default();
params.layer_name = Some("some_table_name");
 
let df = df_from_resource("postgresql://user:pass@host/db_name", Some(params)).unwrap();
println!("{}", df);

示例6：来自DataFrame的GeoJSON字节

use polars_gdal::{gdal, gdal_bytes_from_df, WriteParams};

let df: DataFrame = ...;
let json_driver = gdal::DriverManager::get_driver_by_name("GeoJSON")?;
let geojson_bytes = gdal_bytes_from_df(&df, &json_driver, None)?;

示例7：从DataFrame将shapefile写入磁盘

use polars_gdal::{gdal, gdal_resource_from_df, WriteParams};

let df: DataFrame = ...;
let shapefile_driver = gdal::DriverManager::get_driver_by_name("ESRI Shapefile")?;
let _dataset = gdal_resource_from_df(&df, &shapefile_driver, "/some/path/on/disk/my_shapefile.shp", None)?;