# Interpolation Feature in Webi reports to avoid Graph Breaks.

Hi All,

This blog helps you achieving the scenario where we require continuous line graphs without breaks.

We have options to plot null values for the dimension value which has no data and keep the graph continuous. But in our scenario, we didn’t wanted 0 values for empty measures.

This is achieved through use of Interpolation Formula.

What is Interpolation: It helps in calculation of empty measure values against dimension values. By using this we make sure that graph plotted is continuous rather than disconnected lines and points.

It calculates the missing values based on linear equation f(x) = ax + b that passes through adjacent values of missing values.

We do not have any specific trick to use Interpolation. It’s a straight forward formula to be used to calculate the Y axis values for missing data on X-axis.

Scenario: We have 2 datasets with different values for Time Elapsed dimension in both the datasets. A graph Is to be plotted with fixed interval X axis and continuous graph values without discontinuity.

Dataset 1:

Dataset 2:

Expected Result: A single line graph with continuous lines for fixed range of 0-200 on X-axis for all measure from both the datasets.

Resolution:

Requirement 1:

X axis – Merged Values for Time elapsed from Both Datasets – Fixed Intervals from 0 to 200.

Solution:

1. Merge Time Elapsed dimension from both the datasets.

2. Map it to X-axis

3. Set Property – Use of continuous axis layout with fixed tick density.

Requirement 2: Plot a continuous Line Graph for the measure values from both the datasets against a fixed x – axis.

Merged Dataset: We see empty measure values against Time elapsed for the measures.

Graph:

This gives us the discontinuous layout for graph

Here, Required Graphical Layout is to be continuous graph. This is achieved through concept of interpolation.

With the use of interpolation, we calculate values for empty measures against each dimension value and further plot the graph on it to achieve our requirement.

Interpolation is a direct available formula in formula editor:

Syntax: Interpolation ();

Dataset after using Interpolation:

Graph:

With the help of this feature, we were able to plot a continuous graph for fixed time axis values for all measures. It was a nice find as a part of our report requirements.

Hope this helps!!

Thanks Ramneet, very helpful