diff --git a/src/decoders/TileDecoder.cc b/src/decoders/TileDecoder.cc
index 2d8d1e78..4731b58c 100644
--- a/src/decoders/TileDecoder.cc
+++ b/src/decoders/TileDecoder.cc
@@ -55,7 +55,6 @@ string TileDecoder::weights() {
     }
     if (mode_ == "opencharts" ) 
         out <<  parent << "/opencharts-cache-" << grid_ << ".nc";
-        
     else 
         out << parent << "/weight-" << grid_ << "-" << projection() << "-z" + tostring(z_) << ".nc";
     return out.str();
@@ -67,7 +66,10 @@ string TileDecoder::positions() {
     if (parent.empty()) {
         parent = buildSharePath("tiles");
     }
-    out << parent << "/wind-" << grid_ << "-" << projection() << "-z" + tostring(z_) << ".nc";
+    if (mode_ == "opencharts" ) 
+        out <<  parent << "/opencharts-wind-" << grid_ << ".nc";
+    else 
+        out << parent << "/wind-" << grid_ << "-" << projection() << "-z" + tostring(z_) << ".nc";
 
     return out.str();
 }
@@ -78,7 +80,12 @@ string TileDecoder::positions_symbols() {
     if (parent.empty()) {
         parent = buildSharePath("tiles");
     }
-    out << parent << "/symbol-" << grid_ << "-" << projection() << "-z" + tostring(z_) << ".nc";
+    if (mode_ == "opencharts" ) {
+        out <<  parent << "/opencharts-symbol-" << grid_ << ".nc";
+    }
+
+    else 
+        out << parent << "/symbol-" << grid_ << "-" << projection() << "-z" + tostring(z_) << ".nc";
     file_ = ifstream(out.str());
     if (file_.good()) {
         file_.close();
@@ -110,6 +117,20 @@ bool TileDecoder::ok() {
     grid_         = string(val);
 
     string path = weights();
+    if (mode_ == "opencharts" ) {
+        try {
+            Netcdf netcdf(path, "index");
+            map<string, string> first, last;
+            static vector<double> latitudes;
+            netcdf.get(projection_ + "_lat", latitudes, first, last);
+            return true;
+        }
+        catch(...) {
+            return false;
+        }
+    }
+
+
     file_       = ifstream(path);
     if (!file_.good()) {
         file_.close();
@@ -158,17 +179,29 @@ void TileDecoder::customisedPoints(const Transformation& transformation, const s
 #ifdef HAVE_NETCDF
     Netcdf netcdf(path, "index");
 
-    map<string, string> first, last;
-    first["x"] = tostring(x_);
-    first["y"] = tostring(y_);
-    last["x"]  = tostring(x_);
-    last["y"]  = tostring(y_);
-    vector<double> bbox;
     vector<double> latitudes;
     vector<double> longitudes;
     vector<double> values;
     vector<int> index;
 
+    map<string, string> first, last;
+
+    if ( mode_ == "opencharts") {
+
+        // netcdf.get(projection_ + "_lat", latitudes, first, last);
+        // netcdf.get(projection_ + "_lon", longitudes, first, last);
+        netcdf.get(projection_ + "_index", values, first, last);
+       
+    }
+    else {
+        first["x"] = tostring(x_);
+        first["y"] = tostring(y_);
+        last["x"]  = tostring(x_);
+        last["y"]  = tostring(y_);
+        netcdf.get("index", values, first, last);
+    }
+    
+
     int error;
 
     FILE* in = fopen(file_name_.c_str(), "rb");
@@ -193,9 +226,6 @@ void TileDecoder::customisedPoints(const Transformation& transformation, const s
         return;
     }
 
-    int nbpoints = netcdf.getDimension("points");
-    // netcdf.get("bounding-box", bbox, first, last);
-    netcdf.get("index", values, first, last);
 
     for (auto b = values.begin(); b != values.end(); ++b) {
         double lat = *b;
@@ -249,21 +279,36 @@ void TileDecoder::customisedPoints(const Transformation& transformation, const s
 PointsHandler& TileDecoder::points(const Transformation& t, bool) {
     string path = positions_symbols();
     Timer timer("Tile", path);
+   
 
 #ifdef HAVE_NETCDF
     Netcdf netcdf(path, "index");
 
-    map<string, string> first, last;
-    first["x"] = tostring(x_);
-    first["y"] = tostring(y_);
-    last["x"]  = tostring(x_);
-    last["y"]  = tostring(y_);
-    // vector<double> bbox;
-    static vector<double> latitudes;
-    static vector<double> longitudes;
-    static vector<double> values;
+    vector<double> latitudes;
+    vector<double> longitudes;
+    vector<double> values;
     vector<int> index;
 
+    map<string, string> first, last;
+
+    if ( mode_ == "opencharts") {
+
+        // netcdf.get(projection_ + "_lat", latitudes, first, last);
+        // netcdf.get(projection_ + "_lon", longitudes, first, last);
+        netcdf.get(projection_ + "_index", values, first, last);
+
+
+       
+    }
+    else {
+        first["x"] = tostring(x_);
+        first["y"] = tostring(y_);
+        last["x"]  = tostring(x_);
+        last["y"]  = tostring(y_);
+        netcdf.get("index", values, first, last);
+    }
+    
+
     int error;
 
     FILE* in = fopen(file_name_.c_str(), "rb");
@@ -285,12 +330,8 @@ PointsHandler& TileDecoder::points(const Transformation& t, bool) {
         return *(pointsHandlers_.back());
     }
 
-
+    
     if (latitudes.size() == 0) {
-        int nbpoints = netcdf.getDimension("points");
-        // netcdf.get("bounding-box", bbox, first, last);
-        netcdf.get("index", values, first, last);
-
 
         for (auto b = values.begin(); b != values.end(); ++b) {
             double lat = *b;
@@ -302,11 +343,10 @@ PointsHandler& TileDecoder::points(const Transformation& t, bool) {
             if (i != 0) {
                 if (lon > 180)
                     lon -= 360;
-                // transformation.fast_reproject(lon, lat);
-
                 latitudes.push_back(lat);
                 longitudes.push_back(lon);
                 index.push_back(i);
+                
             }
         }
     }