diff --git a/plugins/layer_types/openlayers_layer_type_geojson.inc b/plugins/layer_types/openlayers_layer_type_geojson.inc
index 69d9530..23a8a5f 100644
--- a/plugins/layer_types/openlayers_layer_type_geojson.inc
+++ b/plugins/layer_types/openlayers_layer_type_geojson.inc
@@ -66,6 +66,25 @@ class openlayers_layer_type_geojson extends openlayers_layer_type {
'#description' => t('Bounding Box strategy will add a query string onto the GeoJSON URL, which means that only data in the viewport of the map will be loaded. This can be helpful if you have lots of data coming from the feed.'),
'#default_value' => isset($this->data['useBBOX']) ? $this->data['useBBOX'] : FALSE,
),
+ //see http://dev.openlayers.org/docs/files/OpenLayers/Strategy/BBOX-js.html#OpenLayers.Strategy.BBOX.resFactor
+ 'resFactor' => array(
+ '#type' => 'select',
+ '#title' => t('Used to determine when previously requested features are invalid (set to 1 if unsure)'),
+ '#description' => t('The resFactor will be compared to the resolution of the previous request to the current map resolution.
+ If resFactor > (old / new) and 1/resFactor < (old / new).
+