Blitzortung.org Forum

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In lightningmaps charts, does the spot mark where the lightning hit the ground, where it originated or in between?

There was a methane explosion last night at about 19:17 hours at the Severn Trent Green recycling plant in Cassington, near Oxford.

But looking at the maps for the last 24 hours, the nearest strikes were three miles away?

(2023-10-03, 10:03)kelper Wrote: [ -> ]In lightningmaps charts, does the spot mark where the lightning hit the ground, where it originated or in between?

There was a methane explosion last night at about 19:17 hours at the Severn Trent Green recycling plant in Cassington, near Oxford.

But looking at the maps for the last 24 hours, the nearest strikes were three miles away?

Theoretically, it's the ground point... if everything were absolutely perfect and stations standardized, it could be within meters of accuracy.... keeping in mind that a discharge stroke has the potential to be many miles long, and the 'best data' from stations should contain a pre-charge, and strong, sharp discharge impulse, followed by at least three zero crossings in group, with perfect timing and stable relative gains, there will be 'deviation' error.  8 or so stations would have to be within about 50 km to produce this precision.  With  'deviation' inherent, rarely does the actual 'ground' point coincide with displayed location... the goal is to generally be within a km and within 300m is cause for celebration... I PERSONALLY have seen 3 plotted strokes over the years, near my location that were actually within meters of the confirmed 'ground point'. That deviation inherent in a 'citizens low-cost' network is one reason Blitzortung remains classified as 'hobbyist'.

(2023-10-03, 22:44)cutty Wrote: [ -> ]

(2023-10-03, 10:03)kelper Wrote: [ -> ]In lightningmaps charts, does the spot mark where the lightning hit the ground, where it originated or in between?

There was a methane explosion last night at about 19:17 hours at the Severn Trent Green recycling plant in Cassington, near Oxford.

But looking at the maps for the last 24 hours, the nearest strikes were three miles away?

Theoretically, it's the ground point... if everything were absolutely perfect and stations standardized, it could be within meters of accuracy.... keeping in mind that a discharge stroke has the potential to be many miles long, and the 'best data' from stations should contain a pre-charge, and strong, sharp discharge impulse, followed by at least three zero crossings in group, with perfect timing and stable relative gains, there will be 'deviation' error.  8 or so stations would have to be within about 50 km to produce this precision.  With  'deviation' inherent, rarely does the actual 'ground' point coincide with displayed location... the goal is to generally be within a km and within 300m is cause for celebration... I PERSONALLY have seen 3 plotted strokes over the years, near my location that were actually within meters of the confirmed 'ground point'. That deviation inherent in a 'citizens low-cost' network is one reason Blitzortung remains classified as 'hobbyist'.

LET ME FOLLOW UP with this:
IF you use vector map on Blitzortung.org and mouseover & click a white stroke (approximately last 20 minutes - this function may vary)

So, using the approximate 'discharge' speed (not 'speed of light') of 150km/sec, the error for THIS specific impulse is actually between .6km to 1.8km since we have an 'averaged' location for the ground point, outside the 'speed of light' assumed deviation of 1.2km. The ground point expected, theoretically, for this stroke, IF it is in fact a C-G impulse, should be within a 1.8km diameter circle of the plotted coordinates.... There are conditions that suggest  IT COULD, in fact, be further away, or closer,  depending on the actual characteristics of the impulse,etc., ...and if the impulse is a C-C or I-C stroke, there will be NO ground point, and 'aerial' location may be vague or  indeterminate at best, regardless of computed location. An impulse can be MANY miles in length!

Read with interest - many thanks again sir, unless you are a lady?

(2023-10-05, 14:11)kelper Wrote: [ -> ]Read with interest - many thanks again sir, unless you are a lady?

Sir... definitely. But, not with 'Honors'...