Measuring and calculating the map


OK, so I’ve about run outta something to do, probably need to get back on that Harley or something. But using the scale on the map, I figured I could figure how far across the map a reporting plane should travel at its reported speed between 90 second refreshes. No big deal for sure, but I did find that a plane will sometimes travel nearly twice as far during the 90 second refresh cycle as it did during the prior refresh, while reporting the same speed each time. I pretty sure this has little to do with anything at all, but I did note same just the same. Where this crazy notion came from was me trying to figure I could figure ‘bout when a plane oughtta be over me taking into account the six minute delay thing and all. Course that has nothing to do with the plane not moving the same amount for the same speed in the same time. So now, have at me, but I wuz a tryin’. Whatcha think y’all? God bless. :confused:


I did find that a plane will sometimes travel nearly twice as far during the 90 second refresh cycle as it did during the prior refresh…

Two words describe this: Time Warp (or is that one word?)


The refresh rates aren’t 100% consistent and neither are the radar updates. It’s likely that in the 90 or so seconds between refreshes, we received two position updates and perhaps the previous time there weren’t any.


Thank you for the thoughts. I find the refresh rates to be pretty much on the money though at 90 seconds. Now that the reporting might get a little outta whack would sure explain my notion though, which seems a bit more likely. Anyway, I was downright proud of my calculations, measuring and all! I guess that they just didn’t work did indeed diminish it a little though. Sure filled a little time though and I guess it didn’t hurt anything. Preshate your thinking on it 'cause I figure you’re pretty close at it. Have a good one.


Hey dbaker, y’all gettin’ that rain down in Houston huh? Lord, we couldn’t buy one for a couple of months in north Louisiana then a couple nights ago we got nearly 5 inches! I felt lucky though, only got about a quarter inch in the kitchen. I appreciate you and this program, it’s quite enjoyable and helpful also. The best to you, and thanks. Pon


With screen refreshes every 90 seconds and position updates every 60 seconds (for most IFR flights over the US), it should alternate between moving 1 “distance” and 2 “distances” (3 position updates in 2 screen refreshes).


There you go, that sounds like my problem right there. I didn’t know there was a difference between reporting and screen refresh times. Thanks so much. Have a good one.