diff --git a/src/dem.rs b/src/dem.rs
index 33c1906..16ed4e9 100644
--- a/src/dem.rs
+++ b/src/dem.rs
@@ -14,15 +14,16 @@ use gdal::Dataset;
 use gdal;
 use tracing_subscriber::registry::Data;
 
-use crate::{SharedState};
+use crate::{DSC};
 
 struct Pos {
     lat: f64,
     lon: f64,
 }
 
-struct MyDataset(OnceCell<Dataset>);
-pub unsafe impl Send for MyDataset{}
+pub struct MyDataset{pub ds: Dataset}
+unsafe impl Send for MyDataset{}
+unsafe impl Sync for MyDataset{}
 
 #[derive(Default)]
 pub struct DatasetCache {
@@ -42,7 +43,7 @@ impl DatasetCache {
 
         if !self.hm.contains_key(&filename){
             let ds = Dataset::open(filename.clone()).unwrap();
-            self.hm.insert(filename.clone(), MyDataset(OnceCell::new(ds)));
+            self.hm.insert(filename.clone(), MyDataset{ds: ds});
         }
 
 
@@ -87,7 +88,7 @@ fn geo_to_pixel(dataset: &Dataset, lat: f64, lon: f64) -> Result<(isize, isize),
     Ok((x_pixel, y_pixel))
 }
 
-pub async fn elevation_from_coordinates(dsc: SharedState, lat: f64, lon: f64) -> f64 {
+pub async fn elevation_from_coordinates(dsc: DSC, lat: f64, lon: f64) -> f64 {
     let file = get_filename_from_latlon(lat, lon);
     let full_filename = format!("data/{file}");
 
@@ -102,8 +103,15 @@ pub async fn elevation_from_coordinates(dsc: SharedState, lat: f64, lon: f64) ->
     //    ds = dd;
     //    //ds = cache.await.get_dataset_for_filename(full_filename);
     //}
-    let x = dsc.get_dataset_for_filename(full_filename);
-    let ds = x.0.read().unwrap();
+    //let x = dsc.get_dataset_for_filename(full_filename);
+
+    if !dsc.contains_key(&full_filename) {
+        println!(">>> WILL GET {full_filename} because not in cache!");
+        let ds = Arc::new(MyDataset{ds:Dataset::open(full_filename.clone()).unwrap()});
+        dsc.insert(full_filename.clone(), ds).await;
+    }
+
+    let ds = &dsc.get(&full_filename).await.unwrap().ds;
     
 
     //let ds = dsc.get_dataset_for_filename(full_filename);
diff --git a/src/main.rs b/src/main.rs
index e121f1a..379e5fa 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -9,31 +9,39 @@ use axum_macros::debug_handler;
 use axum::{
     body::Bytes, extract::{Path, State}, http::StatusCode, routing::{get, post}, Json, Router
 };
-use dem::DatasetCache;
+use dem::{DatasetCache, MyDataset};
 
 use gdal::Dataset;
+use moka::future::Cache;
 
-pub type SharedState = Arc<DatasetCache>;
 
 //#[derive(Default)]
 //struct AppState {
 //    db: RwLock<HashMap<String, Dataset>>,
 //}
 
+type DSC = Cache<String, Arc<MyDataset>>;
+
 #[tokio::main(flavor = "current_thread")]
 async fn main() {
     // initialize tracing
     tracing_subscriber::fmt::init();
 
 
-    let data_set_cache = SharedState::default(); //Arc::new(RwLock::new(dem::DatasetCache::new()));
+        // Evict based on the number of entries in the cache.
+    let cache = Cache::builder()
+        // Up to 10,000 entries.
+        .max_capacity(10_000)
+        // Create the cache.
+        .build();
+    //cache.insert("hello".to_string(), Arc::new(dem::MyDataset{ds: Dataset::open("oueou").unwrap()})).await;
 
     // build our application with a route
     let app = Router::new()
         // `GET /` goes to `root`
         .route("/", get(root))
         .route("/elevation/:lat/:lon", get(get_elevation))
-        .with_state(Arc::clone(&data_set_cache));
+        .with_state(cache);
 
     // run our app with hyper, listening globally on port 3000
     let listener = tokio::net::TcpListener::bind("0.0.0.0:3000").await.unwrap();
@@ -48,7 +56,7 @@ async fn root() -> &'static str {
 
 //async fn get_elevation(State(data_set_cache): State<Arc<RwLock<DatasetCache>>>, Path((lat, lon)): Path<(f64, f64)>) -> String{
 #[debug_handler]
-async fn get_elevation(State(shared): State<SharedState>, Path((lat, lon)): Path<(f64, f64)>) -> String{
+async fn get_elevation(State(shared): State<DSC>, Path((lat, lon)): Path<(f64, f64)>) -> String{
 
 //   let x = AppState::default();
  //   x.db.get("hello");