GeoJSON — Intentionally Invalid: Ring With Only Three Positions
Intentionally invalid: a ring of three positions that closes back on itself and therefore encloses nothing. RFC 7946 requires at least four positions for a linear ring, and this is the shape a simplification pass produces when it over-thins a small polygon.
{
"type": "FeatureCollection",
"features": [
{
"type": "Feature",
"id": "bad-degenerate",
"properties": {
"name": "Collapsed parcel",
"defect": "closed ring has 3 positions, minimum is 4"
},
"geometry": {
"type": "Polygon",
"coordinates": [
[
[
-12.49,
47.06
],
[
-12.474,
47.06
],
[
-12.49,
47.06
]
]
]
}
}
]
}
Specifications
- Format
- GeoJSON (RFC 7946)
- Crs
- WGS 84 (EPSG:4326)
- Coordinate Order
- longitude, latitude
- Encoding
- UTF-8
- Line Endings
- LF
- Features
- 1
- Ring Positions
- 3
- Minimum Required
- 4
- Enclosed Area
- 0
- Spec Section
- RFC 7946 section 3.1.6
- Valid
- false
- Defect
- intentionally invalid — degenerate ring encloses no area
Testing contract
Expected to fail- Scenario
- Validate the geometry and attempt to compute its area.
- Expected result
- The ring is rejected for having fewer than four positions; if a tool accepts it, the area is exactly zero.
What is a .geojson file?
GeoJSON is a JSON-based format for encoding geographic data structures such as points, lines, and polygons, along with their properties. It uses WGS84 longitude-latitude coordinates and standard feature and feature-collection objects. It is a common interchange format for web mapping and GIS.
How to use this file
Use an example GeoJSON file to test geometry parsing, coordinate handling, and mapping libraries or GIS pipelines that render or analyze spatial features.
How to use this file for testing
“GeoJSON — Intentionally Invalid: Ring With Only Three Positions” is a deterministic Novus Examples fixture for Geospatial, Error handling, Schema validation. GeoJSON, GPX, and KML files with points, lines, polygons, and tracks — for testing map tools, route parsers, and geo importers.
Documented properties for this file: UTF-8 · LF · intentionally invalid. Compare results against paired or grouped companions on this page when present (clean↔damaged, searchable↔scanned, or format twins) so scores stay reproducible across runs.
Download the file once, keep the path stable in CI or local scripts, and treat the spec table as the contract: dimensions, seeds, field lists, and roles are intentional. Corrupt or invalid samples are labelled as such — expect parsers to fail loudly rather than silently accept them.
Geospatial fixtures publish one invented territory across formats, with the coordinate reference system and feature counts documented in specs. Convert or reproject and diff against the twin in the same group; edge-case geometries state exactly which assumption they are built to break.
Code examples
import geopandas as gpd
gdf = gpd.read_file("ring-three-positions.geojson")
print(gdf.head())
print(gdf.crs)Related files
- geojsonGeoJSON — Intentionally Invalid: Coordinates as JSON StringsIntentionally invalid: the file is perfectly good JSON but the coordinates are quoted strings, which RFC 7946 does not allow. It is exactly what a CSV-to-GeoJSON script produces when it forgets to cast, and a permissive reader will coerce it and hide the bug.
- geojsonGeoJSON — Intentionally Invalid: Latitude Outside -90 to 90Intentionally invalid: latitude 95, five degrees past the north pole. This is the value that appears when longitude and latitude have been swapped somewhere upstream, so catching it early usually finds an axis-order bug rather than a data-entry one.
- geojsonGeoJSON — Intentionally Invalid: Longitude Outside -180 to 180Intentionally invalid: a point at longitude 200. It is a plausible-looking number that usually comes from adding an offset without wrapping, and it survives JSON schema checks that only test for `number`.
- wktWKT — Intentionally Invalid: Four Malformed ValuesIntentionally invalid: four WKT strings that each break in a different way — a point with one ordinate, a line whose last vertex is ragged, a polygon missing a closing bracket, and a misspelled keyword. Good parsers report which line and which character failed.
- geojsonGeoJSON — Antimeridian Line Split per RFC 7946The same transect cut at the 180th meridian into a two-part MultiLineString, which is what RFC 7946 section 3.1.9 recommends. The split latitude is the linear interpolation of the unsplit twin, so the two files describe the same ground path.
- geojsonGeoJSON — Antimeridian Polygon Split into a MultiPolygonThe straddling block cut at 180 into two polygons that share an edge on the meridian — the interoperable form. Use it as the expected output when testing an antimeridian-splitting routine against the unsplit twin.
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