diff --git a/docs/html/NormalsRegularizationBorders.html b/docs/html/NormalsRegularizationBorders.html
index 79e800f2..634eaf32 100644
--- a/docs/html/NormalsRegularizationBorders.html
+++ b/docs/html/NormalsRegularizationBorders.html
@@ -92,6 +92,8 @@ <h1>NormalsRegularizationBorders</h1><p>
 <tr class=""><td class="m-0"><div class="h-100 config-tree depth-0"><div class="h-100 config mustset">outputfileOutside</div></div></td><td>filename</td><td></td></tr>
 <tr class="table-light"><td class="m-0"><div class="h-100 config-tree depth-0"><div class="h-100 config mustset-unbounded">grid</div></div></td><td><a href="gridType.html">grid</a></td><td>nodal point distribution of parameters, e.g harmonics splines</td></tr>
 <tr class=""><td class="m-0"><div class="h-100 config-tree depth-0"><div class="h-100 config mustset-unbounded">border</div></div></td><td><a href="borderType.html">border</a></td><td>regularization areas, e.g land and ocean</td></tr>
+<tr class="table-light"><td class="m-0"><div class="h-100 config-tree depth-0"><div class="h-100 config optional">R</div></div></td><td>double</td><td>reference radius for ellipsoidal coordinates for border</td></tr>
+<tr class=""><td class="m-0"><div class="h-100 config-tree depth-0"><div class="h-100 config optional">inverseFlattening</div></div></td><td>double</td><td>reference flattening for ellipsoidal coordinates for border, 0: spherical coordinates</td></tr>
 </table>
 
         </div>
diff --git a/docs/latex/programs.auto.tex b/docs/latex/programs.auto.tex
index c6fe95fc..47799d80 100644
--- a/docs/latex/programs.auto.tex
+++ b/docs/latex/programs.auto.tex
@@ -5450,6 +5450,8 @@ \subsection{NormalsRegularizationBorders}\label{NormalsRegularizationBorders}
 \hfuzz=500pt\includegraphics[width=1em]{element-mustset.pdf}~outputfileOutside & \hfuzz=500pt filename & \hfuzz=500pt \\
 \hfuzz=500pt\includegraphics[width=1em]{element-mustset-unbounded.pdf}~grid & \hfuzz=500pt \hyperref[gridType]{grid} & \hfuzz=500pt nodal point distribution of parameters, e.g harmonics splines\\
 \hfuzz=500pt\includegraphics[width=1em]{element-mustset-unbounded.pdf}~border & \hfuzz=500pt \hyperref[borderType]{border} & \hfuzz=500pt regularization areas, e.g land and ocean\\
+\hfuzz=500pt\includegraphics[width=1em]{element.pdf}~R & \hfuzz=500pt double & \hfuzz=500pt reference radius for ellipsoidal coordinates for border\\
+\hfuzz=500pt\includegraphics[width=1em]{element.pdf}~inverseFlattening & \hfuzz=500pt double & \hfuzz=500pt reference flattening for ellipsoidal coordinates for border, 0: spherical coordinates\\
 \hline
 \end{tabularx}
 
diff --git a/groops.xsd b/groops.xsd
index da8d3b7d..bf42ca93 100644
--- a/groops.xsd
+++ b/groops.xsd
@@ -16924,6 +16924,16 @@
 								<xs:documentation>regularization areas, e.g land and ocean</xs:documentation>
 							</xs:annotation>
 						</xs:element>
+						<xs:element name="R" type="double" minOccurs="0" default="6378137.0">
+							<xs:annotation>
+								<xs:documentation>reference radius for ellipsoidal coordinates for border</xs:documentation>
+							</xs:annotation>
+						</xs:element>
+						<xs:element name="inverseFlattening" type="double" minOccurs="0" default="298.2572221010">
+							<xs:annotation>
+								<xs:documentation>reference flattening for ellipsoidal coordinates for border, 0: spherical coordinates</xs:documentation>
+							</xs:annotation>
+						</xs:element>
 					</xs:sequence>
 				</xs:complexType>
 			</xs:element>
diff --git a/source/programs/normals/normalsRegularizationBorders.cpp b/source/programs/normals/normalsRegularizationBorders.cpp
index e67b6bb9..14399b0b 100644
--- a/source/programs/normals/normalsRegularizationBorders.cpp
+++ b/source/programs/normals/normalsRegularizationBorders.cpp
@@ -61,14 +61,18 @@ void NormalsRegularizationBorders::run(Config &config, Parallel::CommunicatorPtr
     FileName  insideName, outsideName;
     GridPtr   grid;
     BorderPtr border;
+    Double    a, f;
 
     readConfig(config, "outputfileInside",  insideName,  Config::MUSTSET,  "", "");
     readConfig(config, "outputfileOutside", outsideName, Config::MUSTSET,  "", "");
     readConfig(config, "grid",              grid,        Config::MUSTSET, "", "nodal point distribution of parameters, e.g harmonics splines");
     readConfig(config, "border",            border,      Config::MUSTSET, "", "regularization areas, e.g land and ocean");
+    readConfig(config, "R",                 a,           Config::DEFAULT,  STRING_DEFAULT_GRS80_a, "reference radius for ellipsoidal coordinates for border");
+    readConfig(config, "inverseFlattening", f,           Config::DEFAULT,  STRING_DEFAULT_GRS80_f, "reference flattening for ellipsoidal coordinates for border, 0: spherical coordinates");
     if(isCreateSchema(config)) return;
 
 
+    Ellipsoid ellipsoid(a, f);
     std::vector<Vector3d> points = grid->points();
     logInfo<<"  nodal points: "<<points.size()<<Log::endl;
 
@@ -77,7 +81,7 @@ void NormalsRegularizationBorders::run(Config &config, Parallel::CommunicatorPtr
 
     for(UInt k=0; k<points.size(); k++)
     {
-      if(border->isInnerPoint(points.at(k)))
+      if(border->isInnerPoint(points.at(k), ellipsoid))
         diag1(k)=1;
       else
         diag2(k)=1;