FlightAware Discussions

Signal Strength Heatmap

Image one looks as i would have expected the map to loo like. (Traffic above 25’000)

Image two appears to be missing any data however this was expected as there was no low level traffic during the capture.

Image three appears to have my location plotted at the very top of the image and not central for some reason. My lat/lon is 56 / -2 but the image appears to plot from 0 - 60 lat.

As you can see, all appear to be missing the green terrain outlines and airports etc.

heatmap.sh won’t produce the plots with the outlines. That’s the first version of the script and is much more basic. From memory it doesn’t explicitly set the ranges for each axis, so if there’s not much data it may look odd. The one that produces all the other plots is polar.sh.

If you have timelapse1090 installed, polar.sh can use the data it collects to produce the plots, so you don’t have to use nonup to do it.

You can do:

./ polar.sh -1

rather than set the time and interval.

Thanks for the quick reply, caius :slight_smile: and that explains why i don’t have the full set heatmaps - I was only running ./heatmap.sh and not ./polar.sh !

I have only installed timelapse1090 this morning but have had graphs1090 installed for over a week, so i’m not sure if ./ polar.sh -1 timelapse1090 will work?

One thing i noticed on the ./polar.sh run is that i can now successfully view the output at http:///dump1090-fa/plots/ :grinning: The only issue is the RSSI range is set from -2 to 0 so nothing appears to have been plotted. I will need to somehow change this.

EDIT: I now realise the RSSI range was/is governed by the RSSI info gathered, and the scale will adjust as necessary.


I have just ran ./polar.sh 60 1 having made the edit to line 406 as you suggested. I look forward to the output and will post *COLUMN results as asked.

You might find the problem resolves itself with more data. I’ve not seen that error occur before.

If you have timelapse1090 then that will accumulate data for the period set. The script will use all the data that is available. The interval and duration for data collection is set in /etc/default/timelapse

I have mine set for 24 hours collecting every 3 seconds. That produces quite dense plots, but takes correspondingly longer to process. Not so bad on a pi 4 or PC but can take a while on pi 3. If you set it that high though, the actual timelapse web page will probably crash when you load it under normal traffic levels. If you only use it for making these plots then it’s not really a problem.

So i’ve ran ./polar.sh -1 and the COLUMN output was;

    Mean: -9.0034
    Std Dev: 5.2432

When i run ./polar.sh 60 1 i got the following error again.

  • FILE:
    Records: 128633
    Out of range: 0
    Invalid: 0
    Column headers: 0
    Blank: 0
    Data Blocks: 1

    Mean: 0.0000
    Std Dev: 0.0000

Generating all altitudes heatmap…
“/dev/stdin” line 34: Can’t plot with an empty cb range!

The ./polar.sh 60 1 process only produces two files. One PNG polarheatmap-2020-05-21.png and the data file whereas the ./polar.sh -1 produces the full suite of png files and updates the /plots page.

Let me have a play and see if I can reproduce the problem.

Edit - OK I’ve reproduced it and the problem is in the part that grabs the live data from dump1090. I rarely use that way of plotting so I’ve not seen it before. Not sure whether the aircraft.json format has changed slightly or if something else changed.

It should be fixed now - grab the updated polar.sh and give it a try.

The problem was some variables were being defined inside a loop that isn’t used when getting data locally so they never got set. I’ve moved them outside of it so it should now work as intended.

Hi caisus,

So i updated polar.sh and ran a very short ./polar.sh 5 1. the output was as following;

Number of data points collected: 246
Calculating Range, Azimuth and Elevation data:
Filtering altitudes
Generating all altitudes heatmap…
Generating high altitude heatmap…
Generating low altitude heatmap…
"/dev/stdin" line 49: warning: Skipping data file with no valid points
"/dev/stdin" line 49: warning: resetting rrange
Generating close range heatmap
Generating elevation heatmap…
Generating Range/Altitude plot…
Generating Close Range altitude plot
Generating low heatmap with map overlay
"/dev/stdin" line 142: warning: Skipping data file with no valid points
Graphs available at :
Graphs rendered in 311 seconds

For the avoidance of doubt, there was very little traffic visible, and no traffic below 25000ft. I believe this will be why the lines in bold were reporting no valid points?

I am please to say that the full /dump1090/plots is displaying now as expected, allbeit with very little traffic. I will now run a longer sample nohup ./polar.sh 180 3 rate and report back.

Thank you very much for your help and a brilliant script! :slight_smile:

Yes, that will probably be because there’s no data there. The main problem seems to be fixed though.
Looking at this problem I noticed another bug which I’ve also fixed, so it was useful.