topojson.core.extract

Extract

Extract(self, data, options={})

This class targets the following objectives:

1. Detection of geometrical type of the object
2. Extraction of linestrings from the object

The extract function is the first step in the topology computation. The following sequence is adopted:

1. extract
2. join
3. cut
4. dedup
5. hashmap

For each line or polygon geometry in the input hash, including nested geometries as in geometry collections, the coordinates array is replaced with an equivalent "coordinates" array that points to one of the linestrings as indexed in bookkeeping_geoms and stored in linestrings.

For Points geometries count the same, but are stored in coordinates and referenced in bookkeeping_coords.

Parameters

• data : any geometric type

  Different types of a geometry object, originating from shapely, geojson, geopandas and dictionary or list of objects that contain a __geo_interface__.

Returns

• dict

  object created including the keys type, linestrings, coordinates bookkeeping_geoms, bookkeeping_coords, objects

to_dict

Extract.to_dict(self)

Convert the Extract object to a dictionary.

to_svg

Extract.to_svg(self, separate=False)

Display the linestrings as SVG.

Parameters

• separate : boolean

  If True, each of the linestrings will be displayed separately. Default is False