ENH: Adding an isotropic spacing mode, off by default

Code/Projections/otbImageToGenericRSOutputParameters.h

@@ -99,6 +99,11 @@ public:
   itkSetMacro(OutputSize, SizeType);
   itkGetMacro(OutputSize, SizeType);
 
+  /** Isotropic spacing flag */
+  itkSetMacro(EstimateIsotropicSpacing,bool);
+  itkGetMacro(EstimateIsotropicSpacing,bool);
+  itkBooleanMacro(EstimateIsotropicSpacing);
+
   /**
    * Method to Force the use of the spacing selected by the user
    * The output size is computed using this spacing
@@ -175,6 +180,7 @@ private:
 
   bool                          m_ForceSpacing;
   bool                          m_ForceSize;
+  bool                          m_EstimateIsotropicSpacing;
   
 }; // end of class ImageToGenericRSOutputParameters
 

Code/Projections/otbImageToGenericRSOutputParameters.txx

@@ -31,6 +31,7 @@ ImageToGenericRSOutputParameters<TImage>
   m_Transform   = GenericRSTransformType::New();
   m_ForceSpacing = false;
   m_ForceSize    = false;
+  m_EstimateIsotropicSpacing = false;
 }
 
 /**
@@ -217,8 +218,19 @@ ImageToGenericRSOutputParameters<TImage>
 
   // Evaluate spacing
   SpacingType outputSpacing;
-  outputSpacing[0] = sizeCartoX / OxLength;
-  outputSpacing[1] = -sizeCartoY / OyLength;
+
+
+  if(m_EstimateIsotropicSpacing)
+    {
+    double isotropicSpacing = std::min(sizeCartoX / OxLength, sizeCartoY / OyLength);
+    outputSpacing[0] = isotropicSpacing;
+    outputSpacing[1] = -isotropicSpacing;
+    }
+  else
+    {
+    outputSpacing[0] = sizeCartoX / OxLength;
+    outputSpacing[1] = -sizeCartoY / OyLength;
+    }
 
   this->SetOutputSpacing(outputSpacing);
 }