diff --git a/lib/www/client/source/src/views/Map.vue b/lib/www/client/source/src/views/Map.vue
index ae89e77..9be87a8 100644
--- a/lib/www/client/source/src/views/Map.vue
+++ b/lib/www/client/source/src/views/Map.vue
@@ -56,7 +56,7 @@
           <div>
             <v-menu bottom offset-y class="mr-1 pb-1">
               <template v-slot:activator="{ on, attrs }">
-                <v-icon small left class="mx-0" v-bind="attrs" v-on="on">mdi-dots-grid</v-icon>
+                <v-icon small left class="mx-0" v-bind="attrs" v-on="on" :title="`Show deviations.\nCurrently selected mode: ${heatmapTitle}. Click to change`">mdi-dots-grid</v-icon>
               </template>
               <v-list nav dense>
                 <v-list-item @click="setHeatmapValue('total_error')">
@@ -691,6 +691,71 @@ export default {
       return { positions, values, udv };
     },
 
+    heatmapTitle () {
+
+      let title = this.heatmapValue;
+
+      switch (this.heatmapValue) {
+        case "total_error":
+          title = "Total position error (raw data)";
+          break;
+        case "delta_j":
+          title = "Total crossline position error (raw data)";
+          break;
+        case "delta_i":
+          title = "Total inline position error (raw data)";
+          break;
+        case "delta_μ":
+          title = "Guns mean delta error";
+          break;
+        case "delta_σ":
+          title = "Guns delta standard deviation (1⋅σ)";
+          break;
+        case "delta_R":
+          title = "Guns delta range";
+          break;
+        case "press_μ":
+          title = "Fired array guns mean pressure";
+          break;
+        case "press_σ":
+          title = "Fired array pressure standard deviation (1⋅σ)";
+          break;
+        case "press_R":
+          title = "Fired array pressure range";
+          break;
+        case "depth_μ":
+          title = "Guns mean depth";
+          break;
+        case "depth_σ":
+          title = "Gun depth standard deviation (1⋅σ)";
+          break;
+        case "depth_R":
+          title = "Gun depth range";
+          break;
+        case "fill_μ":
+          title = "Guns mean fill time";
+          break;
+        case "fill_σ":
+          title = "Guns fill time standard deviation (1⋅σ)";
+          break;
+        case "fill_R":
+          title = "Guns fill time range";
+          break;
+        case "delay_μ":
+          title = "Guns mean firing delay";
+          break;
+        case "delay_σ":
+          title = "Guns firing delay standard deviation (1⋅σ)";
+          break;
+        case "delay_R":
+          title = "Guns firing delay range";
+          break;
+        default:
+      }
+
+      return title;
+    },
+
     ...mapGetters(['user', 'loading', 'serverEvent', 'lineName', 'serverEvent']),
     ...mapState({projectSchema: state => state.project.projectSchema})
   },