I use Advanced Custom Fields (ACF) to store data in a custom field. I had latitude and longitude information stored separately, but I they need to be in one custom field so I made the function below. $query just queries all the relevant posts.

$query = query_custom_posts(); if($query->have_posts()): 
while ($query->have_posts()): $query->the_post();
if(get_field('map_lat') && get_field('map_lng')):

$lat = get_field('map_lat');
$long = get_field('map_lng');
$coord = $lat.','.$long;
$post_id = get_the_ID();

update_post_meta($post_id, 'map_coor', $coord);

endif; endwhile; wp_reset_query(); endif;


Now the function above works. The field map_coor gets populated with the lat and long separated by a comma (I can see the information in the field).

The weird thing is that if I use get_field('map_coor') on the front-end nothing shows up. If I save the corresponding post, then the info DOES show up.

In the function above I also tried to use the function update_field (from ACF) like this: update_field($post_id, 'map_coor', $coord) but the problem is still there.

So my question is; do I need to alter the function above or just run a function which saves all posts? If the latter is the case; how do I do that? I've found the hook save_posts but I'm not sure how to let it run through all the posts.

1 Answer 1


The problem is that the function update_field from ACF works a little bit different from update_post_meta. Can you see it?

update_post_meta( $post_id, $meta_key, $meta_value, $prev_value );
update_field( $field_key, $value, $post_id );

If you use update_post_meta you should in my opinion use get_post_meta to get the meta. If you use update_field you should use the_field or get_field because ACF stores the key/values-pairs in a slightly different way.

  • 1
    If you use update_field you must use the_field or get_field because ACF stores the key/values-pairs in a slightly different way this is not entirely accurate. it's true that ACF stores values differently, but you can use update_field and retrieve the contents with get_post_meta just fine as long as you use update_field correctly. the important thing to note is that $field_key is not the same thing as $meta_key!
    – Milo
    Nov 1, 2013 at 15:02
  • I changed that to "should in my opinion use". What you said is absolute correct but this "field-name/field-reference"-thing is very often the problem.
    – realloc
    Nov 1, 2013 at 15:06
  • Thanks. Like I've described in my question, I've tried update_field. I've used it in combination with get_field. That gives the same outcome; the field value is saved, but when I query the custom field on the front-end it returns empty. I'll try update_post_meta and replace get_field with get_post_meta.
    – eskimo
    Nov 1, 2013 at 17:18
  • 1
    It does work when I use update_post_meta and get_post_meta. Still think it's strange that update_field and get_field don't give the same results. I'll mark the answer as accepted, thanks again.
    – eskimo
    Nov 1, 2013 at 17:35
  • I am using update_post_meta() and get_field() and it is working -- `update_field() was not working but I still don't know why. Jun 25, 2018 at 16:30

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