Published on June 1, 2020
Starting from Meazurem client version 1.5, it’s possible to export online sensor data to a CSV file. Exporting sensor data to an external file extends your capabilities to use the data.
In this blog post, we use Google Sheets, free online spreadsheet software. It works inside a web browser and thus on all platforms. Google Sheets requires that you have an Google account and that you are signed in.
If you don’t want to use Google Sheets, you can apply most of these instructions on other software too. Alternatives to Google Sheets include Microsoft Excel, Apple Numbers and OpenOffice Calc, for example.
A CSV (comma separated values) file is a text file that contains data in a table form, separated by commas and line breaks. It’s a simple format that can be used for storing and transferring data. The file has a standard format and all spreadsheet programs can open it.
Here’s an example of exported Meazurem sensor data:
Timestamp,Temperature,Humidity,Pressure 2020-05-26T00:00:00.000Z,8.32,75.5,102073 2020-05-26T00:01:00.000Z,8.31,75.5,102074
Exporting data is done per sensor.
To export sensor data with the Android app,
To export sensor data with the iOS app,
After you are in the Export view, pick the start and end times. The selected dates are inclusive. The exported data will contain samples from the beginning of the start date to the end of the end date. To make the export, tap Export.
Exporting huge amount of data from the database is time consuming. That’s why exporting your data will be processed in background. Once the job is one, a download link is sent to your email. It should not take over a minute to receive the link.
This section is quite specifically tailored for Google Sheets. If you use another tool, please refer to the documentation of that tool.
To open a CSV file with Google Sheets,
At this point, you have imported the exported CSV file into a Google Sheets. Next, you will learn how to plot a chart.
Producing a simple chart is very easy. To make a chart,
Charting the data right away is fast but it might not lead to appropriate result. Let’s edit the data to make the chart look better and also present the times correctly.
For example, if one quantity has much different range of values, the chart is hard to visualize. In our sensor data example, the pressure has values much larger than temperature or humidity. This causes the scale of the chart to be improper. Because the chart scale is so large, you basically loose all the temperature and humidity variation information.
There are at least two ways to solve the situation.
The data might have gaps or the data samples are not evenly distributed. It’s impossible to point it from the image but our sample data has a gap.
To solve this problem,
=DATEVALUE(MID(A2,1,10)) + TIMEVALUE(MID(A2,12,8))
Now you should have something like:
Data exported from Meazurem has the timestamp in UTC (Universal Time, Coordinated) timezone. It’s the same as GMT (Greenwich Mean Time).
To make the time to match your local timezone, one more fix is needed. In this example, we use the timezone of Finland. It’s UTC+3 or GMT+3 during summer time.
=DATEVALUE(MID(A2,1,10)) + TIMEVALUE(MID(A2,12,8)) + (3/24)
The data should look something like
Now we have modified the data so that we can plot a visually correct chart.
This time, don’t select all the cells. Select only the columns that you want in the chart. In our example, we will select columns B, C, D and E.
Run the chart tool again to get the final result. Now you have all the quantities presented in the same chart, illustrating the missing data samples too.
Our data sample had one hour gap in the data. This gap is illustrated in the image above with a green circle that is added manually afterwards. The CSV file was missing values for that time range but with our data preparation, we were able to make the chart to notice it. If you compare this image to the first one, you can see that the first simple chart missed the gap totally. This is because the chart didn’t understand that the column A contained time values.
That’s it. Now you are able to make cool charts of your Meazurem online sensor data.
Which ever software you use, learn to use the tool and you can make awesome things with it!
Create a free account and get started with 3000 measurement sample data points.
Having proper indoor temperature and humidity makes you feel better both physically and mentally. You will stay healthier and sleep better.