picogeojson 0.5.0

Usage

GeoJSON files or strings are read using fromfile() or fromstring() (alias loads()).

pt = picogeojson.fromstring('{"type": "Point", "coordinates": [1.0, 3.0]}')
# -> Point(coordinates=[1.0, 3.0])

Sometimes a particular type of GeoJSON object is expected (e.g. from an API GET request), but for safety the type needs to be checked. Alternatively, the result_fromstring() function can be used, which returns an object with safe accessors for specific GeoJSON types.

result = picogeojson.result_fromstring(api_response.decode("utf-8"))

# Expecting one or more points or multipoints
for geom in result.points:
    # do something with points
    # ...

for geom in result.multilinestrings:
    # do something with multilinestrings
    # ...

This works for Features too, and we can filter by the .properties member.

result = picogeojson.result_fromstring(api_response.decode("utf-8"))

for feature in result.features("Polygon", {"type": "Lake", "state": "Oregon"}):
    # do something with lakes in Oregon
    # ...

GeoJSON objects may be constructed in Python and composed (merge()) or split (burst()).

points = [picogeojson.Point((1, 2)),
          picogeojson.Point((3, 4)),
          picogeojson.Point((5, 6))]

merged_points = picogeojson.merge(points)
# -> MultiPoint(coordinates=[(1, 2), (3, 4), (5, 6)])

split_points = picogeojson.burst(merged_points)
# -> [Point((1, 2)), Point((3, 4)), Point((5, 6))]

GeoJSON objects are serialized with tostring() (alias dumps()).

picogeojson.tostring(
    picogeojson.Point([1.0, 3.0])
)
# -> {"coordinates": [1.0, 3.0], "type": "Point"}'

Keyword arguments can be passed to tostring() that - enforce Polygon/MultiPolygon rotation direction, with counterclockwise for external rings and clockwise for internal rings (enforce_poly_winding) - split objects that cross the international dateline into multipart objects, for easier processing (antimeridian_cutting) - control whether a bbox member is computed and added to the JSON output (write_bbox)

picogeojson will leverage ujson as a backend if it is installed. Otherwise, it uses Python’s built-in json module.

Performance

The read benchmark involves reading a list of earthquake features. The write benchmark involves serializing the continent of Australia.

*antimeridian cutting and polygon winding check set to False

This is a standalone Python package extracted from the Karta geojson submodule.