The PurpleAir map graph can be used to see recent historical data displayed in a line graph. Clicking or tapping a sensor on the PurpleAir map will cause the graph to open. The graph will show data for the currently selected data layer. The length of time displayed on the graph will change depending on the averaging period being used. To close the graph, click or tap on the “x” in the top-right corner of the configuration menu window.
Hovering the mouse over or tapping on a point on the graph will display its value and the date and time the entry was collected. Clicking and dragging will allow you to zoom in to a designated zone. While zoomed in, clicking and dragging horizontally while holding down “shift” will pan across the graph. The “Reset zoom” button will return the map to standard zoom.
The graph can compare data from multiple sources. Any number of sensors can be clicked or tapped to overlap their graphs. To highlight the data of a specific channel, hover the mouse cursor over the channel’s name at the bottom of the graph window. Clicking or tapping on the channel name will toggle its visibility. A dashed gray line will display the average of the graph data. Below is an example of where to click to toggle this option.
By clicking on channel A underlined in the image above, only channel B will display, shown by the image below. This is helpful to view sensors with one channel reporting erroneously high, as this will make the other channel’s data easily viewable.
Clicking or tapping on the three horizontal lines menu icon (hamburger menu) on the graph window will provide more options. Selecting “View in full screen” will cause the graph to fill the space of your screen. While in full screen, the menu option will switch to “Exit from full screen.” Options are available to download an image of the graph as a PNG, JPG, PDF, or SVG. The data that appears in the graph can be downloaded by selecting “Download CSV” or “Download XLS.” More information on downloading is available here: Download Map Graph Data.
Thanks for posting this description. Would be great to see a link to this from the map page graph section itself, I don’t think most initial or casual users are going to know to look in the forums for this info. Maybe also a note about the download icon hidden in the bottom left corner of the map.
Hi @jcothran, this is a great idea. I will input it as a feature request to be looked into.
can you tell me what A & B is ? What is the meaning of those two ?
Hi @CDVTA, PA-II edition sensors contain two laser counters that read the air quality independently. If you select a sensor on the PurpleAir map, you will likely see two lines that appear on the graph. Each of these lines represents a single channel in that sensor. They are named channel A and channel B.
Thanks, this is useful! I have some suggestions for the UI, and a question.
It is very non-intuitive that the way to get the drop down menus to show up is to click in the tiny grey space above the plot. Maybe you could have words to click to get it to show up. Also, it would be nice to have words to click to hide it. The intuitive way to hide it would be to click on the ‘x’, but that makes the entire plot go away (but oddly not the drop down menus).
There should be simple instructions somewhere on the page that tells the user: “Click on a sensor to add its data to your plot”. I’ve used this map a dozen times now and have only now figured that out, and not until I read this page did I realize that this is how to have data from multiple sensors.
I’d like a button that would change the horizontal (time) axis on the plot to show the last week, and one for the last month. Currently the only way to change the amount of time displayed (I think) is to change the averaging time. I’d rather just compress the data. And I don’t know offhand how much to change the averaging time to see the last week.
Suggestion 4: the legend for the names of the sensors is in a very very small font. Could there be a way to make them larger?
Question: I thought that before I had found a way to see the average of all the sensors in my neighborhood, but I can’t find that now. Is that possible?
Thanks for all your efforts!
Oh, it would also be nice to have a single button to click to add the data from all the sensors within the current map zoom to my plot. Because somehow they sometimes get unselected on their own and it is tedious to add one by one.
what is the value listed underA and B mean
how the average of the following data is 30
what about data for 2021, when downloading
Many PurpleAir sensors use two laser counters to conduct independent measurements. These are referred to as “Channel A” and “Channel B.” Data can be labeled to indicate which channel it’s from.
Could you provide the sensor index, averaging period, data layer, and time that you obtained the provided data? Did you also obtain this from the map or the API?
Thank You for your swift response. example
(Attachment raw-pm25-us-epa-gm.xls is missing)
I want data from all stations in addis from 2016 or the date of establishment to the end of Dec 30/2023( for the time being from establishment to today) , the humidity, temperature, wind speed and monthly and yearly PM2.5 data.
The dotted average line is an average of all data viewable on the graph. In this case, the average is being affected by the higher readings from 2020.
If you would like to download data for all sensors in Addis, you may want to use our API. To do this, you can follow these steps:
- You’ll first need to create API keys
- Then you’ll want to obtain sensor indexes for all the sensors you want data from
- Finally, you can use the Data Download Tool to download historical data from the API.
Please follow our API Use Guidelines. Additionally, the API is a paid service. However, every user gets some usage for free, and sensor owners can contact us for assistance on obtaining data from their devices.
@listemily These are some fantastic suggestions, and we appreciate the feedback! I’ll pass these along to the map development team.
As for your question about showing averages for all sensors in your neighborhood, if you change the Averaging period, this will change all sensor markers on the map to match the average you’ve chosen.
Hi there. I dont know what happened but the Y line on the graph now extends to 3k. How do I get it back to a more readable level. Perhaps 500? Thanks
We have sent you an email to begin troubleshooting this issue.
A post was merged into an existing topic: PurpleAir Data Validation