How to use the Map Graph

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.

Screen Shot 2022-07-21 at 9.18.02 AM

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.

Screenshot 2023-06-20 at 9.33.59 AM

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.

Screenshot 2023-06-20 at 9.35.33 AM

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.

1 Like

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.

1 Like

Hi @jcothran, this is a great idea. I will input it as a feature request to be looked into.

1 Like

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.

1 Like

Thanks for the details