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package topojson
A functor that takes a Json parsing implementation and returns a TopoJSON parser and constructor.
Parameters
Signature
type json = J.tThe internal representation of JSON
Geometries
TopoJSON objects are primarily made up of geometry primitives that are the same as those used in Geojson. For example you can have a single Point or Linestring.
These are grouped under the Geometry module and in particular the Geometry.geometry type. These can be accessed and pattern-matched against using the Geometry.geometryfunction. For example:
let is_linestring t =
let open Topojson in
match Geometry.geometry t with
| Geometry.LineString _ -> true
| _ -> falsemodule Geometry : sig ... endTopologies
The Topology.t is the most common TopoJSON object for the main document. This contains a map of geometry objects along with other important components of the topology including the arc index and transform information.
module Topology : sig ... endTopoJSON Objects
Finally we have the main TopoJSON object. Most frequently this will be a Topology.t but could technically be a standalone Geometry.t according to the specification.
type topojson = | Topology of Topology.t| Geometry of Geometry.t(*The underlying TopoJSON datastructure.
*)
val topology_exn : t -> Topology.tAccessor for the TopoJSON data. This will try to access a Topology.t.contents
val bbox : t -> float array optionAccessor for the optional bounding-box for the entire TopoJSON object.
Construct a new TopoJSON object, optionally with a bounding-box.
of_json json converts the JSON to a topojson object (a type t) or an error.
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