Shapefile to GeoJSON Converter (SHP to GeoJSON)

How the Shapefile to GeoJSON Converter works, and what it assumes

The Esri shapefile is still the most common way GIS data changes hands. QGIS and ArcGIS export it by default, and census, cadastral, forestry and election boundaries on open-data portals usually come as a .zip of shapefile parts. It is not one file but several that only work together: the .shp holds the shapes, the .dbf the attribute table, the .prj the coordinate system and the optional .cpg the text encoding. The converter unzips the archive in your browser, reads each part, joins shapes to their attribute rows in order, and writes an RFC 7946 FeatureCollection. Outer rings and holes are sorted out from their winding order, so a parcel with a courtyard stays one polygon with a hole.

The .prj file and projections

Shapefiles are often projected: coordinates in metres on UTM, a national grid such as British National Grid, or Lambert-93. GeoJSON must be WGS 84 longitude and latitude (EPSG:4326), which is what Leaflet and every web map expect. The converter reads the WKT in the .prj, identifies the system by its datum and projection parameters rather than by its name, and reprojects every position. The summary names the EPSG code it found and how accurate the datum change is. A .prj that cannot be matched with certainty, or one in feet, is reported instead of being guessed at; check the code with the EPSG Lookup and enter it under Source coordinate system.

"My data shows up in the ocean"

This is the classic shapefile problem, and it always means the coordinates were read in the wrong system. An easting of 512,000 metres read as degrees is off the planet, and degrees read as Web Mercator metres land within a few hundred metres from 0, 0 in the Gulf of Guinea. A missing .prj is the usual cause. When every coordinate fits longitude and latitude the converter assumes WGS 84 and warns you; otherwise it stops and asks for the EPSG code. Our guide why your shapefile shows up in the wrong place walks through the causes and fixes.

How your data is handled

Cadastral, utility and client layers are often confidential, so nothing is uploaded: the archive is unpacked and converted by JavaScript on your device, in a background worker for files over about 10 MB. Converting something else? Use the KML to GeoJSON converter for Google Earth files or the GPX to GeoJSON converter for GPS tracks. Afterwards, reproject to another system with ST_Transform, check the polygons in the Geometry Validator, or check a single position with the Coordinate Converter.

Where this comes up in GIS work

• Publishing a boundary layer from an open-data portal on a Leaflet or Mapbox map, which needs GeoJSON in WGS 84.
• Turning a UTM survey or cadastral shapefile from a consultant into coordinates a JavaScript app can use.
• Converting a single layer for an API or a test fixture without opening QGIS or running ogr2ogr.
• Checking what coordinate system an unfamiliar shapefile is in before loading it into PostGIS.

A worked example

A parcel layer exported from QGIS in WGS 84 / UTM zone 43N. Its parcels.prj reads (shortened):

PROJCS["WGS_1984_UTM_Zone_43N",GEOGCS["GCS_WGS_1984",DATUM["D_WGS_1984",…]],
  PROJECTION["Transverse_Mercator"],PARAMETER["False_Easting",500000.0],
  PARAMETER["Central_Meridian",75.0],PARAMETER["Scale_Factor",0.9996],…,UNIT["Meter",1.0]]

and one record has the point (500000, 1434000) in metres, with PARCEL_ID P-001 and AREA_M2 27500 in the .dbf. The summary reports EPSG:32643 WGS 84 / UTM zone 43N, matched by its datum and projection parameters, and the output is:

{
  "type": "FeatureCollection",
  "features": [
    {
      "type": "Feature",
      "properties": {
        "PARCEL_ID": "P-001",
        "AREA_M2": 27500
      },
      "geometry": {
        "type": "Point",
        "coordinates": [75, 12.971645]
      }
    }
  ]
}

An easting of exactly 500,000 m is the zone's central meridian, 75° E, and the northing becomes 12.971645° N. The number field stays a number, and the source easting and northing are gone, because GeoJSON has one coordinate system only.

Using the Shapefile to GeoJSON Converter

1. Zip the shapefile's files together (.shp, .dbf, .shx and .prj, plus .cpg if there is one), or select them all at once with Ctrl or Cmd held down.
2. Drop the .zip on the upload box or choose Choose file. Load example opens two land parcels in UTM zone 43N.
3. Check Detected coordinate system in the summary. It names the EPSG code read from the .prj and says whether the layer was reprojected.
4. If there is no .prj and the coordinates are not longitude and latitude, enter the EPSG code under Source coordinate system and press Enter.
5. If the .zip holds several shapefiles, choose one under Layer.
6. Copy or download the GeoJSON, or send it to the Geometry Validator to check the polygons.

When the output looks wrong

The shapefile has no .prj file, and its coordinates are not longitude and latitude

Without a .prj nothing says which projection the numbers are in. Ask whoever sent the data, or look at the values: a six-digit easting with a seven-digit northing is usually UTM. Enter the EPSG code, such as 32643 or 32644 for much of peninsular India, and the layer is reprojected.

The coordinate system in the .prj file could not be identified

The .prj names a datum or projection that is not in the offline set, or its units are feet. Enter the EPSG code yourself if the set holds it, or reproject to EPSG:4326 in QGIS (Export, Save Features As, CRS EPSG:4326) and convert the result.

The .zip has no .dbf file for roads.shp

A shapefile is several files that only work together, and the attributes live in the .dbf. Zip the .dbf with the .shp, using exactly the same name before the extension, and convert again.

Names show odd characters such as é instead of é

The .dbf text is in one code page and the .cpg names another, or there is no .cpg and the guess was wrong; the notes say which code page was used. Correct the .cpg file (for example UTF-8 or 1252), or export from QGIS with the encoding set to UTF-8.

Questions about the Shapefile to GeoJSON Converter