GeoShape Transform

The geoshape transform generates a renderer instance that maps GeoJSON features to a shape instance that issues drawing commands. It is intended for use solely with the shape mark type. This transform is similar in functionality to the geopath transform, but rather than generate intermediate SVG path strings, this transform produces a shape instance that directly generates drawing commands during rendering. This transform can result in improved performance when using canvas rendering for dynamic maps.

This transform uses the d3-geo library.

Example

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Transform Parameters

Property	Type	Description
projection	String	The name of the projection to use. If unspecified, the GeoJSON data will not be projected.
field	Field	The data field containing GeoJSON data. If unspecified, the full input data object will be used.
pointRadius	Number \| Expr	Sets the default radius (in pixels) to use when drawing GeoJSON `Point` and `MultiPoint` geometries. An expression value can be used to set the point radius as a function of properties of the input GeoJSON. ≥ 3.1
as	String	The output field at which to write the generated shape instance. The default is `"shape"`.

Usage

{
  "type": "geoshape",
  "projection": "projection"
}

Generates a shape instance for GeoJSON objects, using the specified projection.