diff --git a/doc/eval.creole b/doc/eval.creole
index 87095b1c..565b452c 100644
--- a/doc/eval.creole
+++ b/doc/eval.creole
@@ -89,6 +89,7 @@ If you read a number, unit conversion takes place. The following units are suppo
 | exp | v number | number | Return e raised to the power of v | no standard
 | min | number, [number, [number, ...]] | number | Returns lowest of the input values. | MapCSS 0.2
 | max | number, [number, [number, ...]] | number | Returns highest of the input values. | MapCSS 0.2
+| sum | number, [number, [number, ...]] | number | Returns sum of all input values. | MapCSS 0.2
 | metric | value | number | Converts the input to pixels (or ""). E.g. number('3m') => '1.5' when the scale is '2 meters in 1 pixel'. | MapCSS 0.2
 | metric | value, [string] | number | Converts the input to a number (or "") of the specified unit (parameter 2, default 'px'). E.g. number('2px') => '2' or number('100px', 'm') => '238.86' (at zoom level 16). | no standard
 | zmetric | value | number | Currently not supported, returns '' |
diff --git a/pgmapcss/eval/eval_sum.py b/pgmapcss/eval/eval_sum.py
new file mode 100644
index 00000000..a76c4ab5
--- /dev/null
+++ b/pgmapcss/eval/eval_sum.py
@@ -0,0 +1,37 @@
+class config_eval_sum(config_base):
+    mutable = 3
+
+def eval_sum(param):
+    if len(param) == 0:
+        return ''
+    if len(param) == 1:
+        param = param[0].split(';')
+
+    values = []
+    for v in param:
+        try:
+            v = float(v)
+        except ValueError:
+            v = ''
+        values.append(v)
+
+    values = [ float(v) for v in values if v != '' ]
+
+    if len(values) == 0:
+        return ''
+
+    return float_to_str(sum(values))
+
+# TESTS
+# IN ['1.0', '5', '3']
+# OUT '9'
+# IN ['1.0', '']
+# OUT '1'
+# IN ['1;4;5']
+# OUT '10'
+# IN []
+# OUT ''
+# IN ['1;;5']
+# OUT '6'
+# IN ['']
+# OUT ''
diff --git a/pgmapcss/mode/standalone/footer.inc b/pgmapcss/mode/standalone/footer.inc
index c6b5bf41..ea55ddac 100644
--- a/pgmapcss/mode/standalone/footer.inc
+++ b/pgmapcss/mode/standalone/footer.inc
@@ -77,8 +77,19 @@ if __name__ == '__main__':
         if params.getvalue('srs'):
             parameters['srs'] = int(params.getvalue('srs'))
 
+        if 'meta' in parameters:
+            include_meta = parameters['meta']
+
+        if bounds is None and include_meta != 'only':
+            print("No bounding box defined.")
+            sys.exit(1)
+
+        # re-open stdout to use utf-8 encoding
+        import codecs
+        sys.stdout = codecs.getwriter("utf-8")(sys.stdout.detach())
+
         # print HTML headers
-        print("content-type: text/javascript, charset-utf8")
+        print("content-type: application/javascript; charset=utf-8")
         print()
 
     else:
@@ -199,7 +210,7 @@ if __name__ == '__main__':
             'properties': properties_list,
         }}
 
-        return json.dumps(feature, indent=2)
+        return json.dumps(feature, indent=4, ensure_ascii=False)
 
 
     results = []