Thank you for your response. I'm afraid I'm still having trouble following.
> So area covered would be a rectangle centered on the lat/long with dimensions as specified above.For each detected fire the latitude/longitude is provided for the center point of the spatial element. The track is the north south dimension in km of the spatial element and the scan is the east west dimension. This is described in the FIRMS FAQ https://earthdata.nasa.gov/faq/firms-faq
for MODIS. So area covered would be a rectangle centered on the lat/long with dimensions as specified above.
I've tried specifying the rectangles as you describe and it is immediately clear that something isn't quite right. That is, rather than adjoining end-to-end, each rectangle is offset with respect to its neighbors. My understanding of this is that the satellite isn't moving in a straight North-South direction, but at an angle (this is also clear from the FIRMS fire map https://firms.modaps.eosdis.nasa.gov/map
- click on 'Orbit Tracks and Overpass Times' then select one or more satellites and you'll see what I mean), and the rectangles need to be rotated to reflect that angle. My problem is I can't work out what the angle is, and that is what I am hoping to learn.
> Then you should be able to answer the question, when was the last time MODIS or VIIRS detected a fire at that location.
The downloaded data only specifies when a hotspot was detected and not when a pass was made without any hotspot detected. So I am no closer to having an answer to my question of how to know when the hotspot has cooled. I believe the only way to answer the question is by testing for the hotspot at the time of the next satellite pass, which is why I want to learn how to retrieve or calculate that time.
> I can reach out to experts on the active fire product, geolocation or FIRMS if you have additional questions .
> My email address is:
If you could reach out to the relevant experts I would be most grateful. I've continued the discussion on the forum so that others might benefit but if you prefer I can also email you directly.