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Working with GeoJSON

Learn how to use GeoJSON with GeoETL.

What is GeoJSON?​

GeoJSON is a JSON-based format for encoding geographic data structures.

For detailed information, see the GeoJSON Driver Reference.

Quick Start​

Reading GeoJSON​

Inspect a GeoJSON file:

geoetl-cli info data.geojson --driver GeoJSON

Example output:

Dataset: /path/to/data.geojson
Driver: GeoJSON

=== Geometry Columns ===
+----------+-------------------+-----+
| Column   | Extension         | CRS |
+----------+-------------------+-----+
| geometry | geoarrow.geometry | N/A |
+----------+-------------------+-----+

=== Fields ===
+------------+--------+----------+
| Field      | Type   | Nullable |
+------------+--------+----------+
| name       | String | Yes      |
| population | Int64  | Yes      |
+------------+--------+----------+

Converting from GeoJSON​

To CSV:

geoetl-cli convert \
  --input data.geojson \
  --output data.csv \
  --input-driver GeoJSON \
  --output-driver CSV

To GeoParquet:

geoetl-cli convert \
  --input data.geojson \
  --output data.parquet \
  --input-driver GeoJSON \
  --output-driver GeoParquet

Converting to GeoJSON​

From CSV:

geoetl-cli convert \
  --input data.csv \
  --output data.geojson \
  --input-driver CSV \
  --output-driver GeoJSON \
  --geometry-column wkt

From GeoParquet:

geoetl-cli convert \
  --input data.parquet \
  --output data.geojson \
  --input-driver GeoParquet \
  --output-driver GeoJSON

GeoJSON Structure​

Feature Collection​

The most common GeoJSON structure:

{
  "type": "FeatureCollection",
  "features": [
    {
      "type": "Feature",
      "properties": {
        "name": "San Francisco",
        "population": 873965,
        "state": "California"
      },
      "geometry": {
        "type": "Point",
        "coordinates": [-122.4194, 37.7749]
      }
    },
    {
      "type": "Feature",
      "properties": {
        "name": "New York",
        "population": 8336817,
        "state": "New York"
      },
      "geometry": {
        "type": "Point",
        "coordinates": [-74.006, 40.7128]
      }
    }
  ]
}

Geometry Types​

GeoJSON supports these geometry types:

Point:

{
  "type": "Point",
  "coordinates": [-122.4194, 37.7749]
}

LineString:

{
  "type": "LineString",
  "coordinates": [
    [-122.4194, 37.7749],
    [-74.006, 40.7128]
  ]
}

Polygon:

{
  "type": "Polygon",
  "coordinates": [
    [
      [-122.4, 37.8],
      [-122.4, 37.7],
      [-122.5, 37.7],
      [-122.5, 37.8],
      [-122.4, 37.8]
    ]
  ]
}

MultiPoint:

{
  "type": "MultiPoint",
  "coordinates": [
    [-122.4194, 37.7749],
    [-74.006, 40.7128]
  ]
}

MultiLineString, MultiPolygon, GeometryCollection are also supported.

Troubleshooting​

Invalid JSON​

Error: Parse error in GeoJSON at line 15

Fix: Validate JSON syntax

# Use jq to validate
cat data.geojson | jq . > /dev/null

# Or Python
python3 -m json.tool data.geojson > /dev/null

Wrong Coordinate Order​

Error: Points appear in wrong location

Fix: Ensure [longitude, latitude] order

// Correct: longitude first
"coordinates": [-122.4194, 37.7749]

Missing Properties​

Error: Empty properties object

Fix: Ensure each feature has properties

{
  "type": "Feature",
  "properties": {},  // ❌ Empty
  "geometry": { ... }
}

{
  "type": "Feature",
  "properties": { "name": "value" },  // ✅ Good
  "geometry": { ... }
}

Quick Reference​

Essential Commands​

# Inspect GeoJSON
geoetl-cli info data.geojson -f GeoJSON

# GeoJSON to CSV
geoetl-cli convert -i data.geojson -o data.csv \
  --input-driver GeoJSON --output-driver CSV

# GeoJSON to GeoParquet
geoetl-cli convert -i data.geojson -o data.parquet \
  --input-driver GeoJSON --output-driver GeoParquet

# CSV to GeoJSON
geoetl-cli convert -i data.csv -o data.geojson \
  --input-driver CSV --output-driver GeoJSON \
  --geometry-column wkt

# Validate GeoJSON
geoetl-cli convert -i data.geojson -o validated.geojson \
  --input-driver GeoJSON --output-driver GeoJSON

References​

See Also​