No default map

Hi Elisabeth,

If the field has a default value, then it’s not something that GB can fix.

You will need to check with ACF’s support on this, ask them how to remove the defualt value.

Hello,

ACF only seems to have a Google Map field, is that what you are using?

I am not able to display the map in my local install. Please provide details with your ACF settings. Is it this plugin you are using?

Hi Elisabeth,

After some investigation, the issue is that the ACF OpenStreetMap Field plugin retains the map center coordinates in the database even when the field is cleared — so GB’s “require value to render” sees a non-empty value and renders the map regardless.

The fix involves two parts: a custom GB Pro display condition that checks whether the map field has a valid location, and a small snippet that clears the meta when the field is saved without a marker.

Add the following to your child theme’s functions.php or a code snippets plugin:

class GB_OSM_Map_Condition extends GenerateBlocks_Pro_Condition_Abstract {

    public function evaluate( $rule, $operator, $value, $context = [] ) {
        switch ( $rule ) {
            case 'osm_has_location':
                $post_id = $context['post_id'] ?? get_the_ID();
                wp_cache_delete( $post_id, 'post_meta' );
                $map = get_post_meta( $post_id, 'map', true );
                $has_location = ! empty( $map ) && is_array( $map ) && ! empty( $map['lat'] );
                return 'is' === $operator ? $has_location : ! $has_location;
            default:
                return false;
        }
    }

    public function get_rules() {
        return [
            'osm_has_location' => __( 'OSM Map Has Location', 'generateblocks' ),
        ];
    }

    public function get_rule_metadata( $rule ) {
        return [
            'needs_value'    => true,
            'value_type'     => 'text',
            'supports_multi' => false,
        ];
    }

    public function sanitize_value( $value, $rule ) {
        return sanitize_text_field( $value );
    }
}

add_action( 'generateblocks_register_conditions', function() {
    GenerateBlocks_Pro_Conditions_Registry::register(
        'osm_map',
        [
            'label'     => __( 'OSM Map', 'generateblocks' ),
            'operators' => [ 'is', 'is_not' ],
            'priority'  => 100,
        ],
        'GB_OSM_Map_Condition'
    );
} );

add_action( 'acf/save_post', function( $post_id ) {
    $field_key = 'YOUR_FIELD_KEY';
    $raw = $_POST['acf'][ $field_key ] ?? '';

    if ( empty( $raw ) ) {
        update_post_meta( $post_id, 'map', '' );
        return;
    }

    $data = json_decode( stripslashes( $raw ), true );

    if ( empty( $data['markers'] ) ) {
        update_post_meta( $post_id, 'map', '' );
    }
}, 20 );

Once the code is in place, edit the map block in your GP template and add a Display Condition: OSM Map → OSM Map Has Location → is, with map as the value. The block will then only render when a valid location has been saved.

I have tried this solution locally and it worked. If it doesn’t work for you, you would need to get in touch with the plugin developer and point out this bug.

No problem!

Hi,

How do you enter the coordinates? For example, when I enter coordinates for London: 51.5074, -0.1278, then click the magnify button to search for them, the location is found. When I save the post, I can see the map with the new coordinates in the front end.

When I update or save the post, the coordinates are gone,

Do you mean the coordinates are gone from the field?

It sounds like an issue with the field plugin itself.

Can you remove George’s code and test it again?