## Kriging algorithm

Problem: How does Tecplot calculate Kriging interpolation? Solution: Kriging and the Semivariogram. A semivariogram is a function that determines the relationship between distance and the variance of the data. Tecplot models the semivariogram with a spherical model using the range and zero value specified in the Kriging dialog as well as the variance of the variable(s) selected to krig.  Here are the details: For each variable selected Tecplot calculates the variance […]

## Blanking a corner of plot

Problem: I want to blank my contour plot only in the lower left-hand corner where x < 45 AND y < 30. Solution: You can use equations like the ones below to create a blanking variable equal to 0 only if x < 45 and y < 30. Then you can delete the extra variables {lowerx} and {lowery}. {lowerx} = max (x -45, 0) {lowery} = max (y – 30, […]

## Average of XY Mapping

Problem: In my XY Line plot, I want to show a line for the average value of one of the XY Mappings. Solution: You can have Tecplot calculate and plot the average for a line mapping: In the Mapping Style dialog Copy the line mapping and make sure the copy is shown. On the Curves page, set the Curve Fit for the new mapping to the General Curve Fit (One […]

## Calculate and display normal vectors

Problem: How can I calculate and display vectors normal to a surface? Solution: Load your dataset and then perform the following steps to calculate normal vectors in Tecplot 360 (not available in Tecplot Focus): Click on the Analyze menu and select Calculate Variables Select Grid K Unit Normal (vector) Set the New Var Location to Cell Center or Node, depending on the desired vector location with respect to the grid. […]

## 2D Probe calculation

Problem: What process does Tecplot use for probing? Also for streamtrace placement contour labeling linear interpolation and polyline extraction in 2D. Solution: In two dimensions Tecplot interpolates for dataset values at the chosen point using bilinear interpolation. For triangular cells, this is a straightforward interpolation of the three nodal values of the triangle that encloses the point:1. Determine the triangle that encloses the chosen point. 2. Determine the weighting to […]

## 3D Probe Calculation

Problem: What process does Tecplot use for probing in 3D? Also for streamtrace placement contour labeling linear interpolation and polyline extraction in 3D. Solution: Tecplot determines the tetrahedron that the point is inside and then does a weighted average of the data set values at the four corners of the tetrahedron to get the values at the point. This method is not the most accurate – especially if your grid […]