diff --git a/lib/interfaces/charts.js b/lib/interfaces/charts.js
index dc67560cb..683bad7b8 100644
--- a/lib/interfaces/charts.js
+++ b/lib/interfaces/charts.js
@@ -115,7 +115,7 @@ function loadCharts(app, req) {
 }
 
 function directoryToMapInfo(dir) {
-  const resourceFile = path.join(chartBaseDir, dir, tilemapresource.xml);
+  const resourceFile = path.join(chartBaseDir, dir, 'tilemapresource.xml');
   return fs
     .readFileAsync(resourceFile)
     .then(resXml => {