这里有一个简单的插件，其中包含您链接的插件的convert函数，还有一个简单的WordPress cron设置，可以每天运行，只需确保您更改CUSTOM_FIELD_KEY 和TAXONOMY_NAME 至实际值

<?php
/*
Plugin Name: wpse62432
Plugin URI: http://en.bainternet.info
Description: Answer to http://wordpress.stackexchange.com/questions/62432/copy-clone-associate-custom-field-to-custom-taxonomy
Version: 1.0
Author: bainternet
Author URI: http://en.bainternet.info
*/

function Location_convert( $cf_key, $taxonomy ) {
    global $wpdb;

    $rows = $wpdb->get_results( $wpdb->prepare( "
        SELECT post_id, GROUP_CONCAT( meta_value ) as terms
        FROM $wpdb->postmeta
        WHERE meta_key = %s
        GROUP BY post_id
    ", $cf_key ) );

    foreach ( $rows as $row ) {
        $post_id = $row->post_id;
        $terms = explode( \',\', $row->terms );
        $terms = (array) apply_filters( \'cft_terms_pre\', $terms, $post_id );

        // Convert raw values to term ids
        foreach ( $terms as $i => $term_name ) {
            $term_name = trim( $term_name );

            if ( empty( $term_name ) )
                continue;

            $term = get_term_by( \'name\', $term_name, $taxonomy, ARRAY_A );

            if ( !$term ) {
                $term = wp_insert_term( $term_name, $taxonomy );

                if ( is_wp_error( $term ) ) {
                    self::$errors[$term_name] = $term->get_error_message();
                    continue;
                }
            }

            $terms[ $i ] = (int) $term[\'term_id\'];
        }

        wp_set_object_terms( $row->post_id, $terms, $taxonomy, true );
    }

    return $wpdb->query( $wpdb->prepare( "DELETE FROM $wpdb->postmeta WHERE meta_key = %s", $cf_key ) );
}

add_action(\'location_daily_event\', \'do_this_daily\');

function location_activation() {
    if ( !wp_next_scheduled( \'location_daily_event\' ) ) {
        wp_schedule_event( current_time( \'timestamp\' ), \'daily\', \'location_daily_event\');
    }
}
add_action(\'wp\', \'location_activation\');

function do_this_daily() {
    location_convert(\'CUSTOM_FIELD_KEY\',\'TAXONOMY_NAME\');
}