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User Guide

Getting rid of spikes in sensor data

When performing analyses, it's important to pre-process data in order to get good results. One such example is getting rid of spikes in sensor data. Four different ways are shown here to get rid of said spikes and get the results you are looking for.

  1. Perform a value-based search to look for values smaller than the spikes.

  2. Keep results to exclude the spikes.

  3. When looking at the statistics table, the values are now displayed without considering the spikes.

1__Getting_rid_of_spikes_in_sensor_data_.png
2__Getting_rid_of_spikes_in_sensor_data_.png
3__Getting_rid_of_spikes_in_sensor_data_.png

Advantages: Quick & Easy

Disadvantage: Less flexible for next steps

  1. Create a formula to over clamp the spikes to a lower value (threshold for maximum of spikes).

    if(A>250,250,A)  

    Variable mapping:

    A = Original tag with spikes

  2. When looking at the statistics table, the values are now displayed with an upper limit for the spikes.

    4__Getting_rid_of_spikes_in_sensor_data_.png
    5__Getting_rid_of_spikes_in_sensor_data_.png

Advantages: Simple concept, Flexible

Disadvantage: Small loss of accuracy

  1. Create another formula to use the last good point as a reference point.

    if(A>250,B,A) 

    Variable mapping:

    A = Original tag with spikes

    B = Original tag with spikes, shifted by 1 minute

  2. When looking at the statistics table, the values are now displayed precisely.

    6__Getting_rid_of_spikes_in_sensor_data_.png
    7__Getting_rid_of_spikes_in_sensor_data_.png

Advantage: Accurate

Disadvantage: May require fine-tuning

  1. Create a formula to linearly interpolate between the start and the end value of an interval when the if-condition is not true.

    if(A<250,A,sqrt(-1)) 

    Variable mapping:

    A = Original tag with spikes

  2. When looking at the statistics table, the values are now displayed precisely like in option C.

    8__Getting_rid_of_spikes_in_sensor_data_.png
    9__Getting_rid_of_spikes_in_sensor_data_.png

Advantage: Accurate

Disadvantage: May require fine-tuning