Index: Ringtoets/GrassCoverErosionInwards/src/Ringtoets.GrassCoverErosionInwards.Forms/Views/GrassCoverErosionInwardsHelper.cs
===================================================================
diff -u -r164556e75ddc489940c96a84fd41589a4acbac80 -r686a257dd8e21e34a52b265f85ef4ac4e11e44a3
--- Ringtoets/GrassCoverErosionInwards/src/Ringtoets.GrassCoverErosionInwards.Forms/Views/GrassCoverErosionInwardsHelper.cs	(.../GrassCoverErosionInwardsHelper.cs)	(revision 164556e75ddc489940c96a84fd41589a4acbac80)
+++ Ringtoets/GrassCoverErosionInwards/src/Ringtoets.GrassCoverErosionInwards.Forms/Views/GrassCoverErosionInwardsHelper.cs	(.../GrassCoverErosionInwardsHelper.cs)	(revision 686a257dd8e21e34a52b265f85ef4ac4e11e44a3)
@@ -22,12 +22,13 @@
 using System.Collections.Generic;
 using System.Linq;
 using Core.Common.Base.Geometry;
+using Ringtoets.Common.Data.FailureMechanism;
 using Ringtoets.GrassCoverErosionInwards.Data;
 
 namespace Ringtoets.GrassCoverErosionInwards.Forms.Views
 {
     /// <summary>
-    /// Class holds a method to help <see cref="GrassCoverErosionInwardsScenariosView"/>. 
+    /// Class holds a helper method to help <see cref="GrassCoverErosionInwardsScenariosView"/>. 
     /// </summary>
     public static class GrassCoverErosionInwardsHelper
     {
@@ -36,7 +37,9 @@
         /// </summary>
         /// <param name="sectionResults">The <see cref="GrassCoverErosionInwardsCalculation"/> objects.</param>
         /// <param name="calculations">The <see cref="GrassCoverErosionInwardsFailureMechanismSectionResult"/> objects.</param>
-        /// <returns>A <see cref="Dictionary{K, V}"/> containing a <see cref="IList{T}"/> of <see cref="GrassCoverErosionInwardsFailureMechanismSectionResult"/> objects for each section name which has calculations.</returns>
+        /// <returns>A <see cref="Dictionary{K, V}"/> containing a <see cref="IList{T}"/> 
+        /// of <see cref="GrassCoverErosionInwardsFailureMechanismSectionResult"/> objects 
+        /// for each section name which has calculations.</returns>
         public static Dictionary<string, IList<GrassCoverErosionInwardsCalculation>> CollectCalculationsPerSegment(
             IEnumerable<GrassCoverErosionInwardsFailureMechanismSectionResult> sectionResults,
             IEnumerable<GrassCoverErosionInwardsCalculation> calculations)
@@ -48,49 +51,73 @@
                 return calculationsPerSegment;
             }
 
-            SectionSegments[] sectionSegments =
-                (from sectionResult in sectionResults
-                 let section = sectionResult.Section
-                 let lineSegments = Math2D.ConvertLinePointsToLineSegments(section.Points)
-                 select new SectionSegments(section.Name, lineSegments)
-                ).ToArray();
+            SectionSegments[] sectionSegments = MakeSectionSegments(sectionResults);
 
             foreach (var calculation in calculations)
             {
-                string sectionName = FindSectionForCalculation(sectionSegments, calculation);
-                if (sectionName == null)
+                FailureMechanismSection section = FindSectionForCalculation(sectionSegments, calculation);
+                if (section == null)
                 {
                     continue;
                 }
 
-                UpdateCalculationsOfSegment(calculationsPerSegment, sectionName, calculation);
+                UpdateCalculationsOfSegment(calculationsPerSegment, section.Name, calculation);
             }
             return calculationsPerSegment;
         }
 
-        private static string FindSectionForCalculation(SectionSegments[] sectionSegmentsCollection, GrassCoverErosionInwardsCalculation calculation)
+        /// <summary>
+        /// Determine which <see cref="FailureMechanismSection"/> geometrically contains the <see cref="GrassCoverErosionInwardsCalculation"/>.
+        /// </summary>
+        /// <param name="sectionResults">The <see cref="GrassCoverErosionInwardsFailureMechanismSectionResult"/> objects 
+        /// whose <see cref="FailureMechanismSection"/> are considered.</param>
+        /// <param name="calculation">The <see cref="GrassCoverErosionInwardsCalculation"/>.</param>
+        /// <returns>The containing <see cref="FailureMechanismSection"/>, or <c>null</c>.</returns>
+        public static FailureMechanismSection FailureMechanismSectionForCalculation(
+            IEnumerable<GrassCoverErosionInwardsFailureMechanismSectionResult> sectionResults,
+            GrassCoverErosionInwardsCalculation calculation)
         {
+            if (sectionResults == null || calculation == null)
+            {
+                return null;
+            }
+
+            SectionSegments[] sectionSegments = MakeSectionSegments(sectionResults);
+
+            return FindSectionForCalculation(sectionSegments, calculation);
+        }
+
+        private static SectionSegments[] MakeSectionSegments(IEnumerable<GrassCoverErosionInwardsFailureMechanismSectionResult> sectionResults)
+        {
+            SectionSegments[] sectionSegments =
+                (from sectionResult in sectionResults
+                 let section = sectionResult.Section
+                 select new SectionSegments(section)
+                ).ToArray();
+            return sectionSegments;
+        }
+
+        private static FailureMechanismSection FindSectionForCalculation(SectionSegments[] sectionSegmentsCollection, GrassCoverErosionInwardsCalculation calculation)
+        {
+            var dikeProfile = calculation.InputParameters.DikeProfile;
+            if (dikeProfile == null)
+            {
+                return null;
+            }
+
             var minimumDistance = double.PositiveInfinity;
-            string sectionName = null;
+            FailureMechanismSection section = null;
 
             foreach (var sectionSegments in sectionSegmentsCollection)
             {
-                var dikeProfile = calculation.InputParameters.DikeProfile;
-                if (dikeProfile == null)
+                var distance = sectionSegments.Distance(dikeProfile.WorldReferencePoint);
+                if (distance < minimumDistance)
                 {
-                    continue;
+                    minimumDistance = distance;
+                    section = sectionSegments.Section;
                 }
-
-                var distance = sectionSegments.Segments.Min(segment => segment.GetEuclideanDistanceToPoint(dikeProfile.WorldReferencePoint));
-                if (!(distance < minimumDistance))
-                {
-                    continue;
-                }
-
-                minimumDistance = distance;
-                sectionName = sectionSegments.Name;
             }
-            return sectionName;
+            return section;
         }
 
         private static void UpdateCalculationsOfSegment(Dictionary<string, IList<GrassCoverErosionInwardsCalculation>> calculationsPerSegment,
@@ -104,30 +131,37 @@
         }
 
         /// <summary>
-        /// This class represents a named collection of <see cref="Segment2D"/> objects.
+        /// This class represents the geometry of a <see cref="FailureMechanismSection"/> as a collection of <see cref="Segment2D"/> objects.
         /// </summary>
         private class SectionSegments
         {
+            private readonly IEnumerable<Segment2D> segments;
+
             /// <summary>
             /// Creates a new instance of <see cref="SectionSegments"/>.
             /// </summary>
-            /// <param name="name">The name of a dike section.</param>
-            /// <param name="segments">The <see cref="IEnumerable{Segment2D}"/> representing the geometry of a dike section.</param>
-            public SectionSegments(string name, IEnumerable<Segment2D> segments)
+            /// <param name="section">The <see cref="FailureMechanismSection"/> whose <see cref="FailureMechanismSection.Points"/> 
+            /// this class represents as a collection of <see cref="Segment2D"/> objects.</param>
+            public SectionSegments(FailureMechanismSection section)
             {
-                Name = name;
-                Segments = segments;
+                Section = section;
+                segments = Math2D.ConvertLinePointsToLineSegments(section.Points);
             }
 
             /// <summary>
-            /// Gets the name this <see cref="SectionSegments"/> contains.
+            /// Gets the <see cref="FailureMechanismSection"/>.
             /// </summary>
-            public string Name { get; private set; }
+            public FailureMechanismSection Section { get; private set; }
 
             /// <summary>
-            /// Gets the <see cref="IEnumerable{Segment2D}"/> this <see cref="SectionSegments"/> contains.
+            /// Calculate the Euclidean distance between the <see cref="FailureMechanismSection"/> and a <see cref="Point2D"/>.
             /// </summary>
-            public IEnumerable<Segment2D> Segments { get; private set; }
+            /// <param name="point">The <see cref="Point2D"/>.</param>
+            /// <returns>The Euclidean distance as a <see cref="double"/>.</returns>
+            public double Distance(Point2D point)
+            {
+                return segments.Min(segment => segment.GetEuclideanDistanceToPoint(point));
+            }
         }
     }
 }
\ No newline at end of file
Index: Ringtoets/GrassCoverErosionInwards/src/Ringtoets.GrassCoverErosionInwards.Service/GrassCoverErosionInwardsCalculationActivity.cs
===================================================================
diff -u -r164556e75ddc489940c96a84fd41589a4acbac80 -r686a257dd8e21e34a52b265f85ef4ac4e11e44a3
--- Ringtoets/GrassCoverErosionInwards/src/Ringtoets.GrassCoverErosionInwards.Service/GrassCoverErosionInwardsCalculationActivity.cs	(.../GrassCoverErosionInwardsCalculationActivity.cs)	(revision 164556e75ddc489940c96a84fd41589a4acbac80)
+++ Ringtoets/GrassCoverErosionInwards/src/Ringtoets.GrassCoverErosionInwards.Service/GrassCoverErosionInwardsCalculationActivity.cs	(.../GrassCoverErosionInwardsCalculationActivity.cs)	(revision 686a257dd8e21e34a52b265f85ef4ac4e11e44a3)
@@ -23,6 +23,7 @@
 using System.Linq;
 using Core.Common.Base.Service;
 using Ringtoets.Common.Data.AssessmentSection;
+using Ringtoets.Common.Data.FailureMechanism;
 using Ringtoets.Common.Service;
 using Ringtoets.GrassCoverErosionInwards.Data;
 using Ringtoets.GrassCoverErosionInwards.Forms.Views;
@@ -66,11 +67,9 @@
 
         protected override void OnRun()
         {
-            Dictionary<string, IList<GrassCoverErosionInwardsCalculation>> calculationsPerSegmentName =
-                GrassCoverErosionInwardsHelper.CollectCalculationsPerSegment(failureMechanism.SectionResults, new[]{calculation});
+            FailureMechanismSection failureMechanismSection = 
+                GrassCoverErosionInwardsHelper.FailureMechanismSectionForCalculation(failureMechanism.SectionResults, calculation);
 
-            var failureMechanismSection = failureMechanism.Sections.FirstOrDefault(section => section.Name.Equals(calculationsPerSegmentName.Keys.FirstOrDefault()));
-
             PerformRun(() => GrassCoverErosionInwardsCalculationService.Validate(calculation, assessmentSection),
                        () => calculation.ClearOutput(),
                        () => GrassCoverErosionInwardsCalculationService.Calculate(calculation,
Index: Ringtoets/GrassCoverErosionInwards/test/Ringtoets.GrassCoverErosionInwards.Forms.Test/Views/GrassCoverErosionInwardsViewHelperTest.cs
===================================================================
diff -u -r164556e75ddc489940c96a84fd41589a4acbac80 -r686a257dd8e21e34a52b265f85ef4ac4e11e44a3
--- Ringtoets/GrassCoverErosionInwards/test/Ringtoets.GrassCoverErosionInwards.Forms.Test/Views/GrassCoverErosionInwardsViewHelperTest.cs	(.../GrassCoverErosionInwardsViewHelperTest.cs)	(revision 164556e75ddc489940c96a84fd41589a4acbac80)
+++ Ringtoets/GrassCoverErosionInwards/test/Ringtoets.GrassCoverErosionInwards.Forms.Test/Views/GrassCoverErosionInwardsViewHelperTest.cs	(.../GrassCoverErosionInwardsViewHelperTest.cs)	(revision 686a257dd8e21e34a52b265f85ef4ac4e11e44a3)
@@ -31,7 +31,6 @@
     [TestFixture]
     public class GrassCoverErosionInwardsViewHelperTest
     {
-
         private readonly GrassCoverErosionInwardsFailureMechanismSectionResult[] oneSectionResult = new[]
         {
             new GrassCoverErosionInwardsFailureMechanismSectionResult(
@@ -164,5 +163,89 @@
             Assert.AreEqual(1, collectCalculationsPerSegment["firstSection"].Count);
             Assert.AreEqual(1, collectCalculationsPerSegment["secondSection"].Count);
         }
+
+        [Test]
+        public void FailureMechanismSectionForCalculation_NullParameters_Null()
+        {
+            // Call
+            var failureMechanismSection = GrassCoverErosionInwardsHelper.FailureMechanismSectionForCalculation(null, null);
+
+            // Assert
+            Assert.IsNull(failureMechanismSection);
+        }
+
+        [Test]
+        public void FailureMechanismSectionForCalculation_FirstParameterNull_Null()
+        {
+            // Setup
+            var calculation = new GrassCoverErosionInwardsCalculation();
+
+            // Call
+            var failureMechanismSection = GrassCoverErosionInwardsHelper.FailureMechanismSectionForCalculation(null, calculation);
+
+            // Assert
+            Assert.IsNull(failureMechanismSection);
+        }
+
+        [Test]
+        public void FailureMechanismSectionForCalculation_SecondParameterNull_Null()
+        {
+            // Call
+            var failureMechanismSection = GrassCoverErosionInwardsHelper.FailureMechanismSectionForCalculation(oneSectionResult, null);
+
+            // Assert
+            Assert.IsNull(failureMechanismSection);
+        }
+
+        [Test]
+        public void FailureMechanismSectionForCalculation_ValidEmptyFirstParameter_Null()
+        {
+            // Setup
+            var calculation = new GrassCoverErosionInwardsCalculation();
+
+            // Call
+            var failureMechanismSection = GrassCoverErosionInwardsHelper.FailureMechanismSectionForCalculation(oneSectionResult, calculation);
+
+            // Assert
+            Assert.IsNull(failureMechanismSection);
+        }
+
+        [Test]
+        public void FailureMechanismSectionForCalculation_FirstSectionResultContainsCalculation_FailureMechanismSectionOfFirstSectionResult()
+        {
+            // Setup
+            var calculation = new GrassCoverErosionInwardsCalculation
+            {
+                InputParameters =
+                {
+                    DikeProfile = new DikeProfile(new Point2D(1.1, 2.2), new RoughnessPoint[0], new Point2D[0])
+                }
+            };
+
+            // Call
+            var failureMechanismSection = GrassCoverErosionInwardsHelper.FailureMechanismSectionForCalculation(twoSectionResults, calculation);
+
+            // Assert
+            Assert.AreSame(twoSectionResults[0].Section, failureMechanismSection);
+        }
+
+        [Test]
+        public void FailureMechanismSectionForCalculation_SecondSectionResultContainsCalculation_FailureMechanismSectionOfSecondSectionResult()
+        {
+            // Setup
+            var calculation = new GrassCoverErosionInwardsCalculation
+            {
+                InputParameters =
+                {
+                    DikeProfile = new DikeProfile(new Point2D(50.0, 66.0), new RoughnessPoint[0], new Point2D[0])
+                }
+            };
+
+            // Call
+            var failureMechanismSection = GrassCoverErosionInwardsHelper.FailureMechanismSectionForCalculation(twoSectionResults, calculation);
+
+            // Assert
+            Assert.AreSame(twoSectionResults[1].Section, failureMechanismSection);
+        }
     }
 }
\ No newline at end of file