[GIS] Longitude values in GeoJSON out of range -180 to 180

coordinate systemcoordinatesgeojsonlatitude longitudeqgis

I've extracted a geojson data file from QGIS for a transportation layer.
Now in the file, I can see multiple entries like the following:

        {
            "geometry": {
                "coordinates": [
                    [
                        [
                            482745.218106,
                            6656907.959327
                        ],
                        [
                            482785.825278,
                            6656836.299613
                        ],
                        [
                            482820.460806,
                            6656815.996028
                        ],
                        [
                            482967.36322,
                            6656599.822557
                        ]
                    ]
                ],
                "type": "MultiLineString"
            },
            "properties": {
                "_col": 4194,
                "_row": 5456,
                "_zoom": 13,
                "brunnel": null,
                "class": "service",
                "oneway": 0,
                "ramp": 0,
                "service": null
            },
            "type": "Feature"
        }

I guess in the coordinates are the latitudes and longitudes. Normally, the range of values should be between -180 and 180, but here it isn't. Why?

Best Answer

It looks like someone or some software has projected the co-ordinates into a projection system that is not WGS84 (Lat/Lon). This is not permitted according to the spec.

Since there is no metadata within the Geojson itself, you will need to ask whoever gave you the file what coordinate system it is in, or work it out based on where the data is, what projection people normally use, the bounds of those projections etc.

You can still open the file in software such as QGIS to see it, but without the crucial information of what co-ordinate system it is in you won't be able to project it, and therefore save it back as WGS84 with its real world coordinates for more general viewing. Having said that, your question doesn't make clear why you care / what you want to do with it afterwards.

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