Interactive Geo Maps - Custom Solution to read from custom meta fields

igm-custom-solution.php

<?php
/**
 * Interactive Geo Maps Custom Solution
 *
 * @wordpress-plugin
 * Plugin Name:       Interactive Geo Maps Custom Solution
 * Plugin URI:        https://interactivegeomaps.com
 * Description:       Reads from custom meta fields
 * Version:           1.0.0
 * Author:            Carlos Moreira
 * Author URI:        https://cmoreira.net/
 * License:           GPL-2.0+
 * License URI:       http://www.gnu.org/licenses/gpl-2.0.txt
 */

add_filter( 'igm_add_meta', 'igm_custom_addon', 1 );

/**
 * Filter map output
 * @param array $meta - meta data from the map
 * @return array modified meta 
 */
function igm_custom_addon( $meta ){


            // if we're in the admin, don't do anything, otherwise it will affect map preview
            if( is_admin() ){
                return $meta;
            }

        // get the current post/page
          global $post;
          $id = $post->ID;

          // setup the empty arrays that will store our data
          $regions = [];
          $legendEntries = [];

          // get meta fields
          $map       = get_post_meta( $id, 'map', true );
          $countries = get_post_meta( $id, 'countries', true );
          $colours   = get_post_meta( $id, 'colours', true );

          // explode the countries and colours to get the arrays
          $countries = explode( ',', $countries );
          $colours   = explode( ',', $colours );

          // merge both, using $countries as key
          // this could be done in different ways, 
          // depending on how many parameters you'll need, but since it was just 2 (country + legend ), this works
          $collection = array_combine( $countries, $colours );
          

          // loop entries.
          foreach (  $collection as $region => $colour ) {

                    // prepare region entry
                    $entry = array(
                              'id'             => trim( $region ),
                              'title'          => $region,
                              'tooltipContent' => $region,
                              'content'        => $region,
                              'useDefaults'    => '0', 
                              'fill'           => $colour,
                              'hover'          => $colour,
                    );

                    // add to regions array
                    array_push( $regions, $entry );

                    // prepare legend entry
                    $legend = array(
                        'name' => $region,
                        'fill' => $colour,
                    );

                    array_push(  $legendEntries, $legend );
                

          }

          // set map to display
          $meta['map'] = $map;

          // set the regions
          $meta['regions'] = $regions;

          // create the legend
          $meta['customLegend']['data'] = $legendEntries;

          return $meta;
}