diff --git a/lib/www/client/source/src/components/group-comparison-summary.vue b/lib/www/client/source/src/components/group-comparison-summary.vue
index 80649c0..e3a2834 100644
--- a/lib/www/client/source/src/components/group-comparison-summary.vue
+++ b/lib/www/client/source/src/components/group-comparison-summary.vue
@@ -10,8 +10,8 @@
               <thead>
                 <tr>
                   <th>Metric</th>
-                  <th>X (m)</th>
-                  <th>Y (m)</th>
+                  <th>I (m)</th>
+                  <th>J (m)</th>
                 </tr>
               </thead>
               <tbody>
@@ -34,21 +34,24 @@
             </template>
           </v-simple-table>
 
-          <h3 class="mt-4">Counts</h3>
+          <h3 class="mt-4">Error distribution</h3>
           <ul>
-            <li>Common Points: {{ comparison.common }}</li>
-            <li>Comparison Length: {{ comparison.length }}</li>
-            <li>Baseline Length: {{ comparison.baselineLength }} (Unique: {{ comparison.baselineUniqueLength }})</li>
-            <li>Monitor Length: {{ comparison.monitorLength }} (Unique: {{ comparison.monitorUniqueLength }})</li>
-            <li>Compared Points: {{ comparison.compared }}</li>
+            <li title="Relative to I-axis positive direction">Primary Direction: {{ (comparison.primaryDirection * 180 / Math.PI).toFixed(2) }}°</li>
+            <li>Anisotropy: {{ comparison.anisotropy.toFixed(2) }}</li>
+            <li title="Length of the semi-major axis of the error ellipse">Semi-Major Axis: {{ semiMajorAxis.toFixed(2) }} m</li>
+            <li title="Length of the semi-minor axis of the error ellipse">Semi-Minor Axis: {{ semiMinorAxis.toFixed(2) }} m</li>
+            <li title="Area of the error ellipse">Error Ellipse Area: {{ ellipseArea.toFixed(2) }} m²</li>
           </ul>
 
-          <h3 class="mt-4">Other Metrics</h3>
+          <h3 class="mt-4">Counts</h3>
           <ul>
-            <li>Anisotropy: {{ comparison.anisotropy.toFixed(2) }}</li>
-            <li title="Relative to I-axis positive direction">Primary Direction: {{ (comparison.primaryDirection * 180 / Math.PI).toFixed(2) }}°</li>
-            <li>Timestamp: {{ new Date(comparison.tstamp).toLocaleString() }}</li>
+            <li title="Unique line / point pairs found in both projects">Common Points: {{ comparison.common }}</li>
+            <li title="Total number of points compared, including reshoots, infills, etc.">Comparison Length: {{ comparison.length }}</li>
+            <li title="Number of points in the baseline project">Baseline Points: {{ comparison.baselineLength }} (Unique: {{ comparison.baselineUniqueLength }})</li>
+            <li title="Number of points in the monitor project">Monitor Points: {{ comparison.monitorLength }} (Unique: {{ comparison.monitorUniqueLength }})</li>
           </ul>
+
+          <p class="mt-3" title="Date and time when the comparison was last performed">Computation timestamp: {{ new Date(comparison.tstamp).toLocaleString() }}</p>
         </v-col>
 
         <v-col cols="12" md="6">
@@ -139,10 +142,34 @@ export default {
         Math.abs(this.comparison['μ'][0]),
         Math.abs(this.comparison['μ'][1])
       );
-      const maxExtent = maxMu + 3 * maxSigma;
+      //const maxExtent = maxMu + 3 * maxSigma;
+      const maxExtent = 20;
       return 100 / maxExtent; // Adjust scale to fit within ~200 pixels diameter
     },
 
+    ellipseArea () {
+      if (!this.comparison) return 0;
+      const a = Math.sqrt(this.comparison.eigenvalues[0]);
+      const b = Math.sqrt(this.comparison.eigenvalues[1]);
+      return Math.PI * a * b;
+    },
+
+    semiMajorAxis () {
+      if (!this.comparison) return 0;
+      return Math.max(
+        Math.sqrt(this.comparison.eigenvalues[0]),
+        Math.sqrt(this.comparison.eigenvalues[1])
+      );
+    },
+
+    semiMinorAxis () {
+      if (!this.comparison) return 0;
+      return Math.min(
+        Math.sqrt(this.comparison.eigenvalues[0]),
+        Math.sqrt(this.comparison.eigenvalues[1])
+      );
+    },
+
     meanX () {
       return this.comparison ? this.comparison['μ'][0] : 0;
     },
diff --git a/lib/www/client/source/src/components/group-repeatability-summary.vue b/lib/www/client/source/src/components/group-repeatability-summary.vue
index 0dbe702..4113ad1 100644
--- a/lib/www/client/source/src/components/group-repeatability-summary.vue
+++ b/lib/www/client/source/src/components/group-repeatability-summary.vue
@@ -2,7 +2,7 @@
   <v-card class="ma-1">
     <v-card-title>Group Repeatability Summary</v-card-title>
     <v-card-text>
-      <p>Inline standard deviation (σ_x) for each baseline-monitor pair. Lower values indicate better repeatability. Colors range from green (best) to red (worst).</p>
+      <p>Error ellipse area for each baseline-monitor pair. Lower values indicate better repeatability. Colors range from green (best) to red (worst).</p>
       <v-simple-table dense>
         <thead>
           <tr>
@@ -17,18 +17,19 @@
               <v-tooltip v-if="colIndex > rowIndex" top>
                 <template v-slot:activator="{ on, attrs }">
                   <div
-                    :style="{ backgroundColor: getSigmaXColor(baselineProject.pid, monitorProject.pid), color: 'white', textAlign: 'center', padding: '4px' }"
+                    :style="{ backgroundColor: getEllipseAreaColor(baselineProject.pid, monitorProject.pid), color: 'white', textAlign: 'center', padding: '4px' }"
                     v-bind="attrs"
                     v-on="on"
                     @click="emitInput(baselineProject, monitorProject)"
                   >
-                    {{ formatSigmaX(baselineProject.pid, monitorProject.pid) }}
+                    {{ formatEllipseArea(baselineProject.pid, monitorProject.pid) }}
                   </div>
                 </template>
                 <span v-if="getComp(baselineProject.pid, monitorProject.pid)">
-                  <div>σ_x: {{ getComp(baselineProject.pid, monitorProject.pid).meta['σ'][0].toFixed(2) }} m</div>
-                  <div>σ_y: {{ getComp(baselineProject.pid, monitorProject.pid).meta['σ'][1].toFixed(2) }} m</div>
+                  <div>σ_i: {{ getComp(baselineProject.pid, monitorProject.pid).meta['σ'][0].toFixed(2) }} m</div>
+                  <div>σ_j: {{ getComp(baselineProject.pid, monitorProject.pid).meta['σ'][1].toFixed(2) }} m</div>
                   <div>Anisotropy: {{ getComp(baselineProject.pid, monitorProject.pid).meta.anisotropy.toFixed(0) }}</div>
+                  <div>Ellipse Area: {{ getEllipseArea(baselineProject.pid, monitorProject.pid).toFixed(2) }} m²</div>
                   <div>Primary Direction: {{ formatPrimaryDirection(getComp(baselineProject.pid, monitorProject.pid)) }}°</div>
                 </span>
               </v-tooltip>
@@ -64,30 +65,42 @@ export default {
     compMap () {
       return new Map(this.comparisons.map(c => [`${c.baseline_pid}-${c.monitor_pid}`, c]));
     },
-    minSigmaX () {
+    minEllipseArea () {
       if (!this.comparisons.length) return 0;
-      return Math.min(...this.comparisons.map(c => c.meta['σ'][0]));
+      return Math.min(...this.comparisons.map(c => {
+        const a = Math.sqrt(c.meta.eigenvalues[0]);
+        const b = Math.sqrt(c.meta.eigenvalues[1]);
+        return Math.PI * a * b;
+      }));
     },
-    maxSigmaX () {
+    maxEllipseArea () {
       if (!this.comparisons.length) return 0;
-      return Math.max(...this.comparisons.map(c => c.meta['σ'][0]));
+      return Math.max(...this.comparisons.map(c => {
+        const a = Math.sqrt(c.meta.eigenvalues[0]);
+        const b = Math.sqrt(c.meta.eigenvalues[1]);
+        return Math.PI * a * b;
+      }));
     }
   },
   methods: {
     getComp (basePid, monPid) {
       return this.compMap.get(`${basePid}-${monPid}`);
     },
-    getSigmaX (basePid, monPid) {
-      return this.getComp(basePid, monPid)?.meta?.['σ']?.[0] ?? null;
+    getEllipseArea (basePid, monPid) {
+      const comp = this.getComp(basePid, monPid);
+      if (!comp) return null;
+      const a = Math.sqrt(comp.meta.eigenvalues[0]);
+      const b = Math.sqrt(comp.meta.eigenvalues[1]);
+      return Math.PI * a * b;
     },
-    formatSigmaX (basePid, monPid) {
-      const val = this.getSigmaX(basePid, monPid);
+    formatEllipseArea (basePid, monPid) {
+      const val = this.getEllipseArea(basePid, monPid);
       return val !== null ? val.toFixed(1) : '';
     },
-    getSigmaXColor (basePid, monPid) {
-      const val = this.getSigmaX(basePid, monPid);
+    getEllipseAreaColor (basePid, monPid) {
+      const val = this.getEllipseArea(basePid, monPid);
       if (val === null) return '';
-      const ratio = (val - this.minSigmaX) / (this.maxSigmaX - this.minSigmaX);
+      const ratio = (val - this.minEllipseArea) / (this.maxEllipseArea - this.minEllipseArea);
       const hue = (1 - ratio) * 120;
       return `hsl(${hue}, 70%, 70%)`;
     },