diff --git a/staticmap.module b/staticmap.module
index a3a6211..c72f97d 100644
--- a/staticmap.module
+++ b/staticmap.module
@@ -173,12 +173,12 @@ function staticmap_field_formatter_view($entity_type, $entity, $field, $instance
         $geodata = $field_processor->provideGeodata($items, $settings);
         $parameters = $provider->buildParams($geodata, $settings);
 
-        $url = $provider->apiUri . http_build_query($parameters);
+        $url = $provider->apiUri . http_build_query($parameters, '', '&');
         if (!empty($settings['preset']['cache'])) {
           $uri = static_map_cache_file_uri($entity_type, $entity, $instance, $url);
           if (!file_exists($uri)) {
             static_map_cache_file_delete($entity_type, $entity, $instance);
-            static_map_cache_file_save($provider->apiUri . http_build_query($parameters), $uri);
+            static_map_cache_file_save($provider->apiUri . http_build_query($parameters, '', '&'), $uri);
           }
           $url = file_create_url($uri);
         }