Intgrid: set knnParams.method

src/Intgrid.cc

@@ -370,12 +370,16 @@ public:
             INTGRID_KNN = INTGRID_NN;
             knnParams.k = 1;
             knnParams.kMin = 1;
+            knnParams.extrapolate = true;
+            knnParams.method = KnnMethod::distanceWeighted;
           }
         if (operatorID == INTGRID_DIS)
           {
             INTGRID_KNN = INTGRID_DIS;
             knnParams.k = 4;
             knnParams.kMin = 1;
+            knnParams.extrapolate = true;
+            knnParams.method = KnnMethod::distanceWeighted;
           }
       }
     else if (operatorID == INTGRID_KNN)