STReadMulti

July 24, 2026 · View on GitHub

This extension is to import multiple files e.g. ST_Read_Multi('path/to/*.geojson').

Warning

This is just a temporary, poor man's solution, until ST_Read officially supports multiple file inputs (cf. duckdb/duckdb-spatial#191). You should use this only when you have no choice but to get all the things done in DuckDB. Usually, you should use gdal vector concat (or ogrmerge) to merge the files before importing the data into DuckDB.

Limitations

  • Only GeoJSON, GeoPackages, and Shapefiles are supported.
  • ST_Read_Multi is highly inefficient compared to ST_Read; this eagerly reads all the data and doesn't support pushdown, spatial index, etc.
  • The returned geometry column is actually in WKB, but the type is BLOB, not GEOMETRY. This is because DuckDB doesn't allow extensions to use another extension's type. You need to explicitly convert it by ST_GeomFromWkb.
  • Metadata like bbox or CRS are just ignored.

Usages

Install the extension from community repository first.

INSTALL st_read_multi FROM community;

LOAD st_read_multi;

GeoJSON

FROM ST_Read_Multi('test/data/*.geojson');

┌─────────────────┬────────┬─────────┬───────────────────────────┐
│    geometry     │  val1  │  val2   │         .filename         │
│    geometry     │ double │ varchar │          varchar          │
├─────────────────┼────────┼─────────┼───────────────────────────┤
│ POINT (1 2)     │    1.0 │ a       │ test/data/points.geojson  │
│ POINT (10 20)   │    2.0 │ b       │ test/data/points.geojson  │
│ POINT (100 200) │    5.0 │ c       │ test/data/points2.geojson │
│ POINT (111 222) │    6.0 │ d       │ test/data/points2.geojson │
└─────────────────┴────────┴─────────┴───────────────────────────┘

GeoPackage

-- load all layers
FROM ST_Read_Multi('test/data/*.gpkg');

┌─────────────────┬───────┬─────────┬─────────────────────────────┬───────────────┐
│      geom       │ val1  │  val2   │          .filename          │    .layer     │
│    geometry     │ int32 │ varchar │           varchar           │    varchar    │
├─────────────────┼───────┼─────────┼─────────────────────────────┼───────────────┤
│ POINT (100 200) │     5 │ c       │ test/data/multi_layers.gpkg │ points2_point │
│ POINT (111 222) │     6 │ d       │ test/data/multi_layers.gpkg │ points2_point │
│ POINT (1 2)     │     1 │ a       │ test/data/multi_layers.gpkg │ points_point  │
│ POINT (10 20)   │     2 │ b       │ test/data/multi_layers.gpkg │ points_point  │
│ POINT (1 2)     │     1 │ a       │ test/data/points.gpkg       │ points        │
│ POINT (10 20)   │     2 │ b       │ test/data/points.gpkg       │ points        │
│ POINT (100 200) │     5 │ c       │ test/data/points2.gpkg      │ points        │
│ POINT (111 222) │     6 │ d       │ test/data/points2.gpkg      │ points        │
└─────────────────┴───────┴─────────┴─────────────────────────────┴───────────────┘

-- load specific layers
FROM ST_Read_Multi('test/data/*.gpkg', layer='points');

[WARN] No such layer 'points' in test/data/multi_layers.gpkg
┌─────────────────┬───────┬─────────┬────────────────────────┬─────────┐
│      geom       │ val1  │  val2   │       .filename        │ .layer  │
│    geometry     │ int32 │ varchar │        varchar         │ varchar │
├─────────────────┼───────┼─────────┼────────────────────────┼─────────┤
│ POINT (1 2)     │     1 │ a       │ test/data/points.gpkg  │ points  │
│ POINT (10 20)   │     2 │ b       │ test/data/points.gpkg  │ points  │
│ POINT (100 200) │     5 │ c       │ test/data/points2.gpkg │ points  │
│ POINT (111 222) │     6 │ d       │ test/data/points2.gpkg │ points  │
└─────────────────┴───────┴─────────┴────────────────────────┴─────────┘

Shapefile

FROM ST_Read_Multi('test/data/shapefile_utf8/*.shp');

┌─────────────────┬────────┬─────────┬──────────────────────────────────────┐
│    geometry     │ 属性1  │  属性2  │              .filename               │
│    geometry     │ double │ varchar │               varchar                │
├─────────────────┼────────┼─────────┼──────────────────────────────────────┤
│ POINT (1 2)     │    1.0 │ 値a     │ test/data/shapefile_utf8/points.shp  │
│ POINT (10 20)   │    1.0 │ 値b     │ test/data/shapefile_utf8/points.shp  │
│ POINT (100 200) │    5.0 │ 値c     │ test/data/shapefile_utf8/points2.shp │
│ POINT (111 222) │    6.0 │ 値d     │ test/data/shapefile_utf8/points2.shp │
└─────────────────┴────────┴─────────┴──────────────────────────────────────┘

Notes:

  • Input should be specified as *.shp (not *.dbf).
  • Attribute encoding is read from DBF LDID when available.
  • If LDID is missing, this extension also tries to infer encoding from a sidecar .cpg file.
  • You can explicitly specify an encoding label with encoding='...' (parsed with the same label set as .cpg).
  • Compared to duckdb-spatial's current ST_Read behavior, this is useful when you need to read non-UTF-8 Shapefiles (e.g. CP932/Shift_JIS DBF attributes).