diff --git a/app/routes/home.tsx b/app/routes/home.tsx
index 2ce3571..5808bdb 100644
--- a/app/routes/home.tsx
+++ b/app/routes/home.tsx
@@ -12,6 +12,25 @@ export function meta({ }: Route.MetaArgs) {
 
 type Row = Record<string, number>;
 
+type PlotType = "scatter" | "surface";
+
+const COLORSCALES = [
+  "Viridis",
+  "Plasma",
+  "Inferno",
+  "Magma",
+  "Cividis",
+  "Hot",
+  "Electric",
+  "Bluered",
+  "Portland",
+  "Rainbow",
+  "RdBu",
+  "Earth",
+  "Teal",
+  "Turbo",
+] as const;
+
 export default function Home() {
   const plotRef = useRef<HTMLDivElement>(null);
 
@@ -20,8 +39,33 @@ export default function Home() {
   const [x, setX] = useState("");
   const [y, setY] = useState("");
   const [z, setZ] = useState("");
+  const [plotType, setPlotType] = useState<PlotType>("scatter");
+  const [colorscale, setColorscale] = useState<string>(COLORSCALES[0]);
 
-  // Render plot when axes change
+  // Build surface grid from scattered (x,y,z) points. Returns null if data isn't a grid.
+  function buildSurfaceGrid(): {
+    xUnique: number[];
+    yUnique: number[];
+    zMatrix: number[][];
+  } | null {
+    const xVals = rows.map((r) => Number(r[x]));
+    const yVals = rows.map((r) => Number(r[y]));
+    const zVals = rows.map((r) => Number(r[z]));
+    const xUnique = [...new Set(xVals)].sort((a, b) => a - b);
+    const yUnique = [...new Set(yVals)].sort((a, b) => a - b);
+    const keyToZ = new Map<string, number>();
+    for (let i = 0; i < rows.length; i++) {
+      const k = `${xVals[i]},${yVals[i]}`;
+      if (!keyToZ.has(k)) keyToZ.set(k, zVals[i]);
+    }
+    if (xUnique.length * yUnique.length !== keyToZ.size) return null;
+    const zMatrix: number[][] = yUnique.map((yi) =>
+      xUnique.map((xj) => keyToZ.get(`${xj},${yi}`) ?? NaN)
+    );
+    return { xUnique, yUnique, zMatrix };
+  }
+
+  // Render plot when axes or options change
   useEffect(() => {
     if (!plotRef.current || !x || !y || !z) return;
 
@@ -35,18 +79,30 @@ export default function Home() {
       const yVals = rows.map((r) => Number(r[y]));
       const zVals = rows.map((r) => Number(r[z]));
 
-      const trace = {
-        type: "scatter3d" as const,
-        mode: "markers" as const,
-        x: xVals,
-        y: yVals,
-        z: zVals,
-        marker: {
-          size: 4,
-          color: zVals,
-          colorscale: "Viridis" as const,
-        },
-      };
+      const grid = buildSurfaceGrid();
+      const useSurface = plotType === "surface" && grid !== null;
+
+      const trace = useSurface && grid
+        ? {
+          type: "surface" as const,
+          x: grid.xUnique,
+          y: grid.yUnique,
+          z: grid.zMatrix,
+          colorscale: colorscale as "Viridis",
+          colorbar: { title: { text: z } },
+        }
+        : {
+          type: "scatter3d" as const,
+          mode: "markers" as const,
+          x: xVals,
+          y: yVals,
+          z: zVals,
+          marker: {
+            size: 4,
+            color: zVals,
+            colorscale: colorscale as "Viridis",
+          },
+        };
 
       Plotly.newPlot(
         plotRef.current!,
@@ -69,7 +125,7 @@ export default function Home() {
     return () => {
       cancelled = true;
     };
-  }, [rows, x, y, z]);
+  }, [rows, x, y, z, plotType, colorscale]);
 
 
   function onFile(file: File) {
@@ -188,6 +244,39 @@ export default function Home() {
           </select>
         </Control>
 
+        <Control label="Plot type">
+          <select
+            className="w-full bg-neutral-900 border border-slate-700 rounded px-2 py-1"
+            value={plotType}
+            onChange={(e) => setPlotType(e.target.value as PlotType)}
+          >
+            <option value="scatter">Dots (scatter)</option>
+            <option value="surface">Surface (area)</option>
+          </select>
+        </Control>
+
+        <Control label="Colorscale">
+          <select
+            className="w-full bg-neutral-900 border border-slate-700 rounded px-2 py-1"
+            value={colorscale}
+            onChange={(e) => setColorscale(e.target.value)}
+          >
+            {COLORSCALES.map((name) => (
+              <option key={name} value={name}>
+                {name}
+              </option>
+            ))}
+          </select>
+        </Control>
+
+        {plotType === "surface" &&
+          rows.length > 0 &&
+          buildSurfaceGrid() === null && (
+            <p className="text-xs text-amber-500/90">
+              Surface needs a full X×Y grid of points. Showing dots instead.
+            </p>
+          )}
+
         <button
           onClick={exportPNG}
           className="w-full mt-2 bg-accent text-black text-sm rounded px-2 py-1 hover:opacity-90"