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I'm very new to projections and struggling to convert a map dataset from OSGB36 (Eastings and Northings) to WGS84 (lat/longs).

I've used geopandas to import a shapefile. Now I want to export it as GeoJSON so I can then use Folium to map it on leaflet.js.

If I check the crs variable with .crs I get:

{u'datum': u'OSGB36',
u'k': 0.999601272,
u'lat_0': 49,
u'lon_0': -2,
u'no_defs': True,
u'proj': u'tmerc',
u'units': u'm',
u'x_0': 400000,
u'y_0': -100000} 

Trouble is if I'm a bit lost on the attributes to set to convert it to WGS84:

staffs.to_crs({'datum':"wgs84"})

RuntimeError: projection not named

Can you help?

7

This should work:

staffs.to_crs(epsg=4326)
  • Oh. One problem. The conversion seems to have mapped northings and eastings to the wrong corresponding figure. I guess that's part of the dataset I was given. Don't suppose there's a simple transform? (No problems, if not). – elksie5000 Mar 27 '14 at 19:38
  • Do you mean northings and eastings are reversed? – Marc Pfister Mar 27 '14 at 19:51
  • Yes. I'm very new with this geo stuff. – elksie5000 Mar 27 '14 at 19:54
  • Actually, that's not true. I've just imported it into Folium and now the map displays beautifully. – elksie5000 Mar 27 '14 at 19:56
  • I don't know the source of your specific problem, but it's a common problem for beginners to reverse coordinate orders since in we generally say (latitude, longitude) and (northing, easting), but most mapping software uses cartesian ordering (x,y) and is therefore in a different order. – Marc Pfister Mar 27 '14 at 20:30

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