Heat map and contour chart works in similar way, they used to plot 3d data in 2d, 3d demention is displayed by color.
Below you can find an example of heatmap chart:
Let's create the chart above step by step.
Create a new page in PageManager and open editor of the page.
In the editor add Charts widget to the page.
Now we have chart on the screen, but we need some data to show, to create data open LOGIC tag and
create Data/Eval processes and connect Eval with the following query:
"readAll(point and air and temp).hisRead(lastYear).hisRollup(avg, 1mo)"
Connect Eval's `out` port and Chart's `in`.
Now your logic tab should looks like the screen show below:
In created trace you should choose Chart type "heatmap".
Heatmap requires matrix as input, by default Heatmap chart will take all Number columns to build this matrix,
but if you need you can choose particular columns by "Z" filed.
Also I set "Tipestamp" to "Y" filed and "MMM" to ts-format, so chart will show months in Y axis:
I left "X" empty, as default it will use "column" names for X axis:
After this manipulations you will have chart as at the begging of the article, it shows temperature as color for
all air temperature points grouped by months.