Call to non-existent openlayers_preset_options()

The function can be replaced by:

// Get preset options, filtered to those which have the GeoField source.
  ctools_include('export');
  $maps = ctools_export_crud_load_all('openlayers_maps');
  $map_options = array();
  foreach ($maps as $machine_name => $data) {
    /** @var \Drupal\openlayers\Map\OLMap $map */
    $map = openlayers_object_load('Map', $data);
    foreach ($map->getSources() as $source) {
      if ($source instanceof \Drupal\openlayers\Source\Geofield) {
        $map_options[$machine_name] = $data->name;
      }
    }
  }

This code needs refactoring into a separate function though. As is marked in openlayers_ui.admin.inc line 19: "// Todo: Rewrite properly and create a generic function to load all objects."

Don't forget to turn on the openlayers_geofield module.

I've added a patch for geofield 7.x-2.x which should fix some more openlayers 3 issues all related to the map presets not being available.
Actually I think geofield needs a 3.x branch to match openlayers 3. That way, we don't break openlayers 2 compatibility.

Thanks for the patch. Regarding the new branch - I don't think, it's a good idea, since Leaflet module (and possibly others) also uses Geofield. Generally, formatter modules should maintain compatibility with modules providing fields they operate on, not the other way around.

If we don't make another branch I propose we add another check for the OL version. Either:

$info = system_get_info('module', 'openlayers'); 
if (version_compare($info['version'], '2.0') >= 0) {
// ... do stuff
}

or

if (is_callable('openlayers_preset_options')) {
// ... do stuff
}