TypeError : cell_to_boundary() got an unexpected keyword argument 'geo_json'

[tomrussell-willdan]

cell_to_boundary() not accepting direct assingment of arguement for unpacking.

[ajfriend]

Could you give an example of the behavior you're expecting?

Also, this is for v3.7. You may want to try the new v4.0: pip install h3 --pre

[tomrussell-willdan]

when I use the function I try to pass it explicitly the assignment of a value to the geo_json argurment but it does not like when i do that. the example is

What I expect to do:

useGeoJsonFormat = True
cell_value = '827507fffffffff'
h3.cell_to_boundary(cell_value, geo_json=useGeoJsonFormat)

This thows the error in the title

What I end up having to do that works and is a work around

useGeoJsonFormat = True
cell_value = '827507fffffffff'
h3.cell_to_boundary(cell_value, useGeoJsonFormat)

[dfellis]

Looking through the source code, myself, I'm not sure that geo_json flag still exists?

EDIT: I don't see it in the Cython, either, though I didn't expect it there; more that it'd be at a higher level restructuring it's output.

EDIT2: I did a local check of the repo and there's only one place where the string geo_json exists in the 4.0 beta:

damocles@talyn:~/oss/h3-py(master)$ git grep geo_json
tests/polyfill/test_h3.py:def test_polyfill_geo_json_compliant():

So I think this feature was accidentally dropped during the rewrite for H3 4.0 vs 3.x. @tomrussell-willdan I would say if you need this feature, at the moment you should use h3-py's 3.7.x release, calling h3_to_geo_boundary and @ajfriend can either update the docs to drop this flag, or update the beta to restore this feature.

[tomrussell-willdan]

thanks. I think for now we will stick on 4.0 and just flip the output ourselves. So is the plan to continue having arguements for geo_json conformity and it was just accidently not included or is the plan to not continue supporting it those arguements?

[SebKp]

@tomrussell-willdan with your solution I get:

TypeError: cell_to_boundary() takes 1 positional argument but 2 were given

It seems the flag is gone, and the documentation is out of date (deprecating the flag, and the new naming convention make more sense than before to me).

---

Edit: to get the result in geojson, an option now is to go through shapely:

from shapely import to_geojson
from shapely.geometry import Polygon

to_geojson(Polygon(h3.cell_to_boundary("827507fffffffff")))

Second edit:

NOTE this solution with shapely returns the coordinates in lat/lon ordering, not in lon/lat. If you are looking for lon/lat look under the @ajfriend message below.

Third edit:

Another option to get the geojson in lon/lat coordinates is

to_geojson(Polygon([a[::-1] for a in h3.cell_to_boundary(x)]))

[ajfriend]

You can see the Python docs for the newly-released v4 here: https://uber.github.io/h3-py/polygon_tutorial.html

In v4, an easy way to get a __geo_interface__-style dictionary for the cell boundary would be:

d = h3.cells_to_geo(['827507fffffffff'])

giving:

{'type': 'Polygon',
 'coordinates': (((-3.4710946837530763, 6.357653288041298),
   (-2.159048476284375, 6.645580466394947),
   (-1.9395631182409523, 8.00719366148785),
   (-3.071080368716595, 9.072581251751162),
   (-4.392258230519222, 8.74778122110663),
   (-4.572995371627281, 7.395109809160045),
   (-3.4710946837530763, 6.357653288041298)),)}

which you could convert to a JSON string like:

import json
json.dumps(d)

giving:

{"type": "Polygon", "coordinates": [[[-3.4710946837530763, 6.357653288041298], [-2.159048476284375, 6.645580466394947], [-1.9395631182409523, 8.00719366148785], [-3.071080368716595, 9.072581251751162], [-4.392258230519222, 8.74778122110663], [-4.572995371627281, 7.395109809160045], [-3.4710946837530763, 6.357653288041298]]]}

We haven't yet added it, but maybe we should consider an option to give the GeoJSON string output, in addition to the dictionary output.

(@SebKp, your solution above is close, but it results in lat/lng ordering instead of the lng/lat ordering that GeoJSON expects.)