useUldk React Hook

A powerful and developer-friendly React hook to interact with ULDK (National Spatial Data Infrastructure) services in Poland, providing access to region geometries and administrative divisions.

Installation

npm install useuldk-react

Features

• Fetch voivodeships, districts, tenants, and precincts.
• Retrieve region and parcel geometries by ID.
• Coordinate transformation from EPSG:2180 to EPSG:4326.
• Handles API errors gracefully.

Usage

Importing the Hook

import { useUldk } from 'useuldk-react';

Example Usage

import React, { useEffect } from 'react';
import { useUldk } from 'useuldk-react';

function App() {
  const {
    voivodeships,
    districts,
    fetchDistricts,
    getRegionGeometryById,
    error,
  } = useUldk();

  useEffect(() => {
    fetchDistricts('02'); // Example TERYT code for district
  }, []);

  return (
    <div>
      <h1>Voivodeships</h1>
      {voivodeships.map((v) => (
        <p key={v.value}>{v.label}</p>
      ))}
      {error && <p>Error: {error}</p>}
    </div>
  );
}

export default App;

API Reference

useUldk(props: useUldkPropsType | undefined): UldkReturnType

Parameters

• props?.voivodeship? (string): Optional TERYT code for a voivodeship.
• props?.district? (string): Optional TERYT code for a district.
• props?.tenant? (string): Optional TERYT code for a tenant.

Return

• voivodeships: List of available voivodeships.
• districts: List of available districts.
• fetchDistricts(value: string): Fetch districts based on voivodeship.
• fetchTenants(value: string): Fetch tenants based on district.
• precincts: List of precincts.
• fetchPrecincts(value: string): Fetch precincts based on tenant.
• getRegionGeometryById(regionId: string): Fetch geometry for a region.
• getParcelGeometryById(parcelId: string): Fetch geometry for a parcel.
• error: Error message if fetching fails.

Example for Fetching Region Geometry

const fetchGeometry = async () => {
  const geometry = await getRegionGeometryById("02");
  console.log(geometry);
};

Types

export type Option = {
  label: string;
  value: string;
};

export type UldkReturnType = {
  voivodeships: Option[];
  districts: Option[];
  fetchDistricts: (value: string) => Promise<void>;
  fetchTenants: (value: string) => Promise<void>;
  tenants: Option[];
  fetchPrecincts: (value: string) => Promise<void>;
  precincts: Option[];
  getRegionGeometryById: (regionId: string) => Promise<Geometry | Geometry[] | undefined>;
  getParcelGeometryById: (parcelId: string) => Promise<Geometry | Geometry[] | undefined>;
  error: string | null;
};

export type useUldkPropsType = {
  voivodeship?: string;
  district?: string;
  tenant?: string;
} | undefined;

License

MIT License. See LICENSE file for details.