If you want to merge 2 sets of timestamped data, and they have identical timestamps, you can do so using a Join transform. But, if the timestamps don’t exactly match up (e.g. they have different intervals), you can easily merge them using the Interpolate transform. Here is a simple example of merging timestamped solar panel and weather station data.
Install Easy Data Transform on your PC or Mac, if you haven’t done so already. It will only take a minute. There is a fully fuctional free trial and you don’t have to give us your email or sign up to anything.
Start Easy Data Transform.
Download files solar.zip and unzip it into solar.csv and weather.csv.
Drag the two .csv data files onto Easy Data Transform. It is important that solar.csv is above weather.csv as we want to merge weather.csv into solar.csv (not vice versa).
return ( new Date( $(Timestamp) ) - new Date( "2020-01-01" ) / 1000;
And set New column name to:
Seconds since 2020-01-01
Click the Evaluate button. If you scroll the data table to the right, you should see a new column at the end called Seconds since 2020-01-01.
Repeat the above process for weather.csv so both have an additional Seconds since 2020-01-01 column.
Click the Interpolate button in the left hand pane.
A new Interpolate transform will be added. With the new Interpolate item selected, in the right pane set Top sample column and Bottom sample column to Seconds since 2020-01-01 and the Bottom value column to Temperature (F).
A new column with the interpolated temperature values will be added at the end.
We can then use various other transforms such as: Remove Cols or Rename Cols to tidy up our columns, Filter to remove rows outside the desired date range and Num Format to set the number of decimal places for the interpolated values.
We can now export the merged data. With the second Interpolate item selected click on the To File button in the left pane (you may need to scroll down to see it).
Choose the output file location and format.
Finally you can File>Save your transforms as a .transform file to re-use in the future.
As well as interpolating data, Easy Data Transform also allows you to combine 52 transforms in many other ways to quickly and easily create complex data transformations for numerical, text and date data. See our quick start guide for more details.