@@ -34,6 +34,7 @@ def save_csv(
         flatten_tags: bool = True,
         exclude_fields: Optional[Sequence[str]] = None,
         dialect: Union[str, 'csv.Dialect'] = 'excel',
+        with_header: bool = True,
     ) -> None:
         """Save array elements into a CSV file.
 
@@ -52,13 +53,13 @@ def save_csv(
 
         with file_ctx as fp:
             if flatten_tags and self[0].tags:
-                keys = list(self[0].to_dict().keys()) + list(
+                keys = list(self[0].non_empty_fields) + list(
                     f'tag__{k}' for k in self[0].tags
                 )
                 keys.remove('tags')
             else:
                 flatten_tags = False
-                keys = list(self[0].to_dict().keys())
+                keys = list(self[0].non_empty_fields)
 
             if exclude_fields:
                 for k in exclude_fields:
@@ -67,7 +68,9 @@ def save_csv(
 
             writer = csv.DictWriter(fp, fieldnames=keys, dialect=dialect)
 
-            writer.writeheader()
+            if with_header:
+                writer.writeheader()
+
             from docarray import Document
 
             for d in self:
 
@@ -72,10 +72,17 @@ def plot_embeddings(
             )
 
         self.save_embeddings_csv(os.path.join(path, emb_fn), delimiter='\t')
+
+        _exclude_fields = ('embedding', 'blob', 'scores')
+        with_header = True
+        if len(set(self[0].non_empty_fields).difference(set(_exclude_fields))) <= 1:
+            with_header = False
+
         self.save_csv(
             os.path.join(path, meta_fn),
-            exclude_fields=('embedding', 'blob', 'scores'),
+            exclude_fields=_exclude_fields,
             dialect='excel-tab',
+            with_header=with_header,
         )
 
         _epj_config = {
@@ -103,10 +110,12 @@ def plot_embeddings(
         with open(os.path.join(path, config_fn), 'w') as fp:
             json.dump(_epj_config, fp)
 
-        shutil.copyfile(
-            os.path.join(__resources_path__, 'embedding-projector/index.html'),
-            os.path.join(path, 'index.html'),
-        )
+        import gzip
+
+        with gzip.open(
+            os.path.join(__resources_path__, 'embedding-projector/index.html.gz'), 'rt'
+        ) as fr, open(os.path.join(path, 'index.html'), 'w') as fp:
+            fp.write(fr.read())
 
         if start_server:
 
@@ -153,7 +162,6 @@ def _get_fastapi_app():
             t_m.join()
         return path
 
-
     def plot_image_sprites(
         self,
         output: Optional[str] = None,
 
@@ -109,3 +109,7 @@ def __eq__(self, other):
         if type(self) is type(other):
             return self._data == other._data
         return False
+
+    def __iter__(self):
+        for f in self.non_empty_fields:
+            yield f, getattr(self, f)
@@ -35,9 +35,8 @@ def parse_proto(pb_msg: 'DocumentProto') -> 'Document':
 
 def flush_proto(doc: 'Document') -> 'DocumentProto':
     pb_msg = DocumentProto()
-    for key in doc.non_empty_fields:
+    for key, value in doc:
         try:
-            value = getattr(doc, key)
             if key in ('blob', 'embedding'):
                 flush_ndarray(getattr(pb_msg, key), value)
             elif key in ('chunks', 'matches'):
 
@@ -3,4 +3,4 @@ def __repr__(self):
         return repr(self.to_dict())
 
     def to_dict(self):
-        return {f: getattr(self, f) for f in self.non_empty_fields}
+        return {f: v for f, v in self}