GeoJSON — Intentionally Invalid: Web Mercator Metres in a .geojson File
Intentionally invalid: Web Mercator metres inside a file that claims to be GeoJSON, with a legacy `crs` member as the only hint. RFC 7946 allows exactly one coordinate system, so this file is what a desktop GIS produces when someone exports a projected layer to GeoJSON without reprojecting it first.
{
"type": "FeatureCollection",
"features": [
{
"type": "Feature",
"id": "town-KB",
"properties": {
"name": "Kestrel Bay",
"code": "KB",
"defect": "coordinates are EPSG:3857 metres"
},
"geometry": {
"type": "Point",
"coordinates": [
-1389489.884,
5952526.765
]
}
},
{
"type": "Feature",
"id": "town-MR",
"properties": {
"name": "Marram",
"code": "MR",
"defect": "coordinates are EPSG:3857 metres"
},
"geometry": {
"type": "Point",
"coordinates": [
-1379415.47,
5960374.522
]
}
},
{
"type": "Feature",
"id": "town-HW",
"properties": {
"name": "Holloway",
"code": "HW",
"defect": "coordinates are EPSG:3857 metres"
},
"geometry": {
"type": "Point",
"coordinates": [
-1397170.929,
5945012.626
]
}Specifications
- Format
- GeoJSON-shaped JSON with projected coordinates
- Features
- 5
- Actual Units
- metre (EPSG:3857)
- Required Units
- degree (EPSG:4326)
- Declared Via
- legacy crs member, which RFC 7946 removed
- Valid
- false
- Defect
- intentionally invalid — RFC 7946 mandates WGS 84 longitude/latitude
Testing contract
Expected to fail- Scenario
- Load the file into a web map that assumes RFC 7946 coordinates.
- Expected result
- The features are rejected or plotted absurdly far outside the valid degree range — coordinates near -1,389,000 are visible as metres rather than degrees.
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: Web Mercator Metres in a .geojson File” is a deterministic Novus Examples fixture for Geospatial, Error handling, Conversion testing. 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: intentionally invalid · GeoJSON-shaped JSON with projected coordinates. 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("projected-coordinates-in-geojson.geojson")
print(gdf.head())
print(gdf.crs)Related files
- 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.
- geojsonGeoJSON — Clockwise Exterior Ring (right-hand rule violated)Both rings of the Mill Court parcel are wound the wrong way round: the exterior clockwise, the interior counter-clockwise. RFC 7946 mandates the right-hand rule, and consumers that rely on winding to tell holes from shells will read this polygon inside out.
- geojsonGeoJSON — Intentionally Invalid: Hole Outside Its ShellIntentionally invalid: the second ring is a whole separate parcel filed as an interior ring of the first, which OGC Simple Features forbids. It is what happens when a MultiPolygon is flattened into a Polygon by concatenating rings.
- geojsonGeoJSON — Intentionally Invalid: Self-Intersecting RingIntentionally invalid: a bowtie ring whose two lobes wind in opposite directions, so the shoelace areas nearly cancel. Buffer, intersection and area operations on this geometry return nonsense rather than failing, which is why it belongs in a validation suite.
- geojsonGeoJSON — Intentionally Invalid: Unclosed Polygon RingIntentionally invalid: the parcel's exterior ring omits the repeated closing position that RFC 7946 requires. Many readers close it silently, which hides the producer's bug until a stricter consumer downstream rejects the data.
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