diff --git a/examples/scientific_charts/src/main.rs b/examples/scientific_charts/src/main.rs
index 20d98a94..34ace161 100644
--- a/examples/scientific_charts/src/main.rs
+++ b/examples/scientific_charts/src/main.rs
@@ -2,7 +2,7 @@
 
 use std::f64::consts::PI;
 
-use plotly::common::{ColorScale, ColorScalePalette, Title};
+use plotly::common::{ColorScale, ColorScalePalette, Font, Title};
 use plotly::contour::Contours;
 use plotly::{Contour, HeatMap, Layout, Plot};
 
@@ -102,22 +102,60 @@ fn customizing_spacing_between_x_and_y_ticks() {
 // Heatmaps
 fn basic_heat_map() {
     let z = vec![vec![1, 20, 30], vec![20, 1, 60], vec![30, 60, 1]];
-    let trace = HeatMap::new_z(z);
+    let trace = HeatMap::new_z(z).zmin(1.0).zmax(60.0);
     let mut plot = Plot::new();
     plot.add_trace(trace);
 
     plot.show();
 }
 
+fn customized_heat_map() {
+    let x = (0..100).map(|x| x as f64).collect::<Vec<f64>>();
+    let y = (0..100).map(|y| y as f64).collect::<Vec<f64>>();
+    let z: Vec<Vec<f64>> = x
+        .iter()
+        .map(|x| {
+            y.iter()
+                .map(|y| (x / 5.0).powf(2.0) + (y / 5.0).powf(2.0))
+                .collect::<Vec<f64>>()
+        })
+        .collect::<Vec<Vec<f64>>>();
+
+    let (_z_min, z_max) = z
+        .iter()
+        .flatten()
+        .fold((f64::MAX, f64::MIN), |(min, max), &x| {
+            (min.min(x), max.max(x))
+        });
+
+    let colorscale = ColorScalePalette::Jet;
+
+    let trace = HeatMap::new(x, y, z)
+        .zmin(z_max * 0.4)
+        .zmax(z_max * 0.5)
+        .color_scale(colorscale.into());
+
+    let layout = Layout::new()
+        .title(Title::new("Customized Heatmap"))
+        .font(Font::new().size(32));
+
+    let mut plot = Plot::new();
+    plot.set_layout(layout);
+    plot.add_trace(trace);
+
+    plot.show();
+}
+
 fn main() {
     // Uncomment any of these lines to display the example.
 
     // Contour Plots
-    simple_contour_plot();
-    colorscale_for_contour_plot();
-    customizing_size_and_range_of_a_contour_plots_contours();
-    customizing_spacing_between_x_and_y_ticks();
+    // simple_contour_plot();
+    // colorscale_for_contour_plot();
+    // customizing_size_and_range_of_a_contour_plots_contours();
+    // customizing_spacing_between_x_and_y_ticks();
 
     // Heatmaps
-    basic_heat_map();
+    // basic_heat_map();
+    // customized_heat_map();
 }
diff --git a/plotly/src/traces/heat_map.rs b/plotly/src/traces/heat_map.rs
index 151b6941..07c216ed 100644
--- a/plotly/src/traces/heat_map.rs
+++ b/plotly/src/traces/heat_map.rs
@@ -110,9 +110,9 @@ where
     zauto: Option<bool>,
     #[serde(rename = "zhoverformat")]
     zhover_format: Option<String>,
-    zmax: Option<Z>,
-    zmid: Option<Z>,
-    zmin: Option<Z>,
+    zmax: Option<f64>,
+    zmid: Option<f64>,
+    zmin: Option<f64>,
     zsmooth: Option<Smoothing>,
 }
 
@@ -179,10 +179,10 @@ mod tests {
 
     #[test]
     fn test_serialize_heat_map_z() {
-        let trace = HeatMap::new_z(vec![1.0]);
+        let trace = HeatMap::new_z(vec![vec![1.0]]);
         let expected = json!({
             "type": "heatmap",
-            "z": [1.0],
+            "z": [[1.0]],
         });
 
         assert_eq!(to_value(trace).unwrap(), expected);
@@ -190,37 +190,41 @@ mod tests {
 
     #[test]
     fn test_serialize_heat_map() {
-        let trace = HeatMap::new(vec![0.0, 1.0], vec![2.0, 3.0], vec![4.0, 5.0])
-            .auto_color_scale(true)
-            .color_bar(ColorBar::new())
-            .color_scale(ColorScale::Palette(ColorScalePalette::Picnic))
-            .connect_gaps(false)
-            .hover_info(HoverInfo::None)
-            .hover_label(Label::new())
-            .hover_on_gaps(true)
-            .hover_template("tmpl")
-            .hover_template_array(vec!["tmpl1", "tmpl2"])
-            .hover_text(vec!["hov", "er"])
-            .legend_group("1")
-            .legend_group_title(LegendGroupTitle::new("Legend Group Title"))
-            .name("name")
-            .opacity(0.99)
-            .reverse_scale(false)
-            .show_legend(true)
-            .show_scale(false)
-            .text(vec!["te", "xt"])
-            .transpose(true)
-            .visible(Visible::LegendOnly)
-            .x_axis("x")
-            .x_calendar(Calendar::Hebrew)
-            .y_axis("y")
-            .y_calendar(Calendar::Islamic)
-            .zauto(true)
-            .zhover_format("fmt")
-            .zmax(10.0)
-            .zmid(5.0)
-            .zmin(0.0)
-            .zsmooth(Smoothing::Fast);
+        let trace = HeatMap::new(
+            vec![0.0, 1.0],
+            vec![2.0, 3.0],
+            vec![vec![4.0, 5.0], vec![6.0, 7.0]],
+        )
+        .auto_color_scale(true)
+        .color_bar(ColorBar::new())
+        .color_scale(ColorScale::Palette(ColorScalePalette::Picnic))
+        .connect_gaps(false)
+        .hover_info(HoverInfo::None)
+        .hover_label(Label::new())
+        .hover_on_gaps(true)
+        .hover_template("tmpl")
+        .hover_template_array(vec!["tmpl1", "tmpl2"])
+        .hover_text(vec!["hov", "er"])
+        .legend_group("1")
+        .legend_group_title(LegendGroupTitle::new("Legend Group Title"))
+        .name("name")
+        .opacity(0.99)
+        .reverse_scale(false)
+        .show_legend(true)
+        .show_scale(false)
+        .text(vec!["te", "xt"])
+        .transpose(true)
+        .visible(Visible::LegendOnly)
+        .x_axis("x")
+        .x_calendar(Calendar::Hebrew)
+        .y_axis("y")
+        .y_calendar(Calendar::Islamic)
+        .zauto(true)
+        .zhover_format("fmt")
+        .zmax(10.0)
+        .zmid(5.0)
+        .zmin(0.0)
+        .zsmooth(Smoothing::Fast);
 
         let expected = json!({
             "type": "heatmap",
@@ -249,7 +253,7 @@ mod tests {
             "y": [2.0, 3.0],
             "yaxis": "y",
             "ycalendar": "islamic",
-            "z": [4.0, 5.0],
+            "z": [[4.0, 5.0], [6.0, 7.0]],
             "zauto": true,
             "zhoverformat": "fmt",
             "zmax": 10.0,