diff --git a/plugins/input/geojson/geojson_index_featureset.cpp b/plugins/input/geojson/geojson_index_featureset.cpp
index 03adfb861..a9a6bc732 100644
--- a/plugins/input/geojson/geojson_index_featureset.cpp
+++ b/plugins/input/geojson/geojson_index_featureset.cpp
@@ -77,6 +77,13 @@ geojson_index_featureset::geojson_index_featureset(std::string const& filename,
 
 geojson_index_featureset::~geojson_index_featureset() {}
 
+namespace {
+using namespace boost::spirit;
+//static const mapnik::json::keys_map keys = mapnik::json::get_keys();
+static const mapnik::json::grammar::geojson_grammar_type geojson_g = mapnik::json::geojson_grammar();
+
+}
+
 mapnik::feature_ptr geojson_index_featureset::next()
 {
     while( itr_ != positions_.end())
@@ -98,16 +105,14 @@ mapnik::feature_ptr geojson_index_featureset::next()
         using namespace boost::spirit;
         using space_type = mapnik::json::grammar::space_type;
         using mapnik::json::grammar::iterator_type;
-
         mapnik::json::geojson_value value;
-        auto keys = mapnik::json::get_keys();
-        auto grammar = x3::with<mapnik::json::keys_tag>(std::ref(keys))
-            [ mapnik::json::geojson_grammar() ];
+        auto const grammar = x3::with<mapnik::json::keys_tag>(std::ref(keys_))
+            [ geojson_g ];
         try
         {
             bool result = x3::phrase_parse(start, end, grammar, space_type(), value);
             if (!result) return mapnik::feature_ptr();
-            mapnik::json::create_feature(*feature, value, keys, tr);
+            mapnik::json::create_feature(*feature, value, keys_, tr);
         }
         catch (x3::expectation_failure<std::string::const_iterator> const& ex)
         {
diff --git a/plugins/input/geojson/geojson_index_featureset.hpp b/plugins/input/geojson/geojson_index_featureset.hpp
index 41e8e84ba..4371636b0 100644
--- a/plugins/input/geojson/geojson_index_featureset.hpp
+++ b/plugins/input/geojson/geojson_index_featureset.hpp
@@ -32,6 +32,10 @@
 #include <mapnik/warning_ignore.hpp>
 #include <boost/interprocess/mapped_region.hpp>
 #include <boost/interprocess/streams/bufferstream.hpp>
+#include <boost/bimap.hpp>
+#include <boost/bimap/set_of.hpp>
+#include <boost/bimap/unordered_set_of.hpp>
+#include <boost/assign/list_of.hpp>
 #pragma GCC diagnostic pop
 #include <mapnik/mapped_memory_cache.hpp>
 #endif
@@ -39,6 +43,35 @@
 #include <deque>
 #include <cstdio>
 
+namespace {
+
+using keys_map = boost::bimap<boost::bimaps::unordered_set_of<std::string>,
+                              boost::bimaps::set_of<int>>;
+
+enum well_known_names
+{
+    id = 1,
+    type,
+    features,
+    geometry,
+    coordinates,
+    properties
+};
+
+inline keys_map get_keys()
+{
+    keys_map keys = boost::assign::list_of<keys_map::relation>
+        ("type", well_known_names::type)
+        ("features", well_known_names::features)
+        ("geometry", well_known_names::geometry)
+        ("coordinates", well_known_names::coordinates)
+        ("properties", well_known_names::properties)
+        ("id", well_known_names::id)
+        ;
+    return keys;
+}
+}
+
 class geojson_index_featureset : public mapnik::Featureset
 {
     using value_type = std::pair<std::size_t, std::size_t>;
@@ -59,6 +92,7 @@ private:
     mapnik::context_ptr ctx_;
     std::vector<value_type> positions_;
     std::vector<value_type>::iterator itr_;
+    keys_map keys_ = get_keys();
 };
 
 #endif // GEOJSON_INDEX_FEATURESE_HPP