Receiver range, just the last xx hours

The "to-do" list for Virtual Radar Server is as long as my arm, but if you want to pile more work onto it then this is for you.
Feek
Posts: 3
Joined: Wed Nov 23, 2016 6:22 pm

Receiver range, just the last xx hours

Postby Feek » Wed Nov 23, 2016 6:29 pm

Hello everyone,

I've only recently started tracking aircraft and have got VRS installed, set up and working and it's working well. It really compliments my setup fantastically, thank you to everyone involved.

I really love the receiver range feature but I'd love it even more if there were any way to have it only plot over a certain period of time, say the last 24 or 48 hours. I don't want it to suddenly clear itself, just keep up to date with the previous [insert time here] tracks.

This'll make it nice and easy to spot any propagation changes or problems with aerials/equipment that bring in a slow range reduction.

Has anyone considered this, is this something which could be possible?

Thanks.

agw
Posts: 1896
Joined: Fri Feb 17, 2012 3:20 am

Re: Receiver range, just the last xx hours

Postby agw » Mon Nov 28, 2016 1:25 am

I'm afraid that there's no support for that, no. For that to work I would need to keep track of quite a lot more information. At the moment I keep track of the furthest position for each radial, so that's 360 coordinates for each layer tracked. To have a kind of rolling plot I would first need to add timestamps to those coordinates which isn't too bad, another 8 bytes or so per coordinate, but I would also need to keep coordinates and timestamps for all of the points along the radial that aircraft pass through, up to the outermost point, so that when a coordinate expires I can fall back to the next closest coordinate seen that hasn't yet expired. I could discard closer coordindates along the radial when a new coordindate is added because the closer ones will expire before the newer one, but I suspect it's still going to end up eating a lot of memory to keep all those coordinates stored over 24 or 48 hours.

Feek
Posts: 3
Joined: Wed Nov 23, 2016 6:22 pm

Re: Receiver range, just the last xx hours

Postby Feek » Mon Nov 28, 2016 5:53 pm

Thanks for the reply, that does sound as though it would be a nightmare to implement.

As an alternative, would it be possible to add an option to autopurge all the range information at a set time of day (say midnight but possibly customisable) so that each day gets a new range plot?

73 Keith.

agw
Posts: 1896
Joined: Fri Feb 17, 2012 3:20 am

Re: Receiver range, just the last xx hours

Postby agw » Wed Dec 07, 2016 12:25 am

There's no option at the moment to reset the range plots automatically, but I've added it to the list.

paradiselost
Posts: 83
Joined: Sun Apr 06, 2014 10:22 am
Location: Philippines

Re: Receiver range, just the last xx hours

Postby paradiselost » Sat Jan 07, 2017 10:46 pm

There has always been the option to manually reset the Range Plots for individual receivers from the main VRS window.

In the middle of the page under Feed Status highlight a receiver and right click and select Reset Receiver Range Plot. That will wipe out the old range plots and start fresh from that time forward. Sometimes it is useful to flush your browser cache to force a reload of range data.

paradiselost
Working Example of Version 2.3.0 Virtual Radar Server http://222.127.74.244/virtualradar/
VRS 2.2 Help Files http://222.127.74.244:8080

Feek
Posts: 3
Joined: Wed Nov 23, 2016 6:22 pm

Re: Receiver range, just the last xx hours

Postby Feek » Sat Jan 07, 2017 10:49 pm

Yes, yes I know. We're talking about an automatic purge, not doing it manually.

fedelosa
Posts: 3
Joined: Sun Feb 12, 2017 4:52 am

Re: Receiver range, just the last xx hours

Postby fedelosa » Sun Feb 12, 2017 5:04 am

Hi agw, have you ever thought if it is possible to calculate the range coverage area?

I was thinking about using the range plot coordinates and some method to calculate convex non intersecting polygon area, but can't seem to find the way to convert from coordinates to area units.

agw
Posts: 1896
Joined: Fri Feb 17, 2012 3:20 am

Re: Receiver range, just the last xx hours

Postby agw » Mon Feb 13, 2017 2:38 am

No, never thought about it :) The range plot is really a series of triangles, you could do the same thing - e.g. draw a line from the centre to the furthest distance along 0° north, then draw another line from the centre to the furthest point for 1° and then draw a third line connecting the first two. The area of the triangle described by the lines would be the coverage area. Then repeat for the remaining 359 degrees. My schoolboy geometry is very rusty though, I'd need to look up how to figure out the angles for the line connecting the two furthermost points and how to calculate the area of the triangle.

fedelosa
Posts: 3
Joined: Sun Feb 12, 2017 4:52 am

Re: Receiver range, just the last xx hours

Postby fedelosa » Tue Feb 14, 2017 3:30 am

agw wrote:No, never thought about it :) The range plot is really a series of triangles, you could do the same thing - e.g. draw a line from the centre to the furthest distance along 0° north, then draw another line from the centre to the furthest point for 1° and then draw a third line connecting the first two. The area of the triangle described by the lines would be the coverage area. Then repeat for the remaining 359 degrees. My schoolboy geometry is very rusty though, I'd need to look up how to figure out the angles for the line connecting the two furthermost points and how to calculate the area of the triangle.


Hi! I am doing the math part of this, calculating the 360 circle portions, doing this way I only have to use the distance part of the data, already in legible and human units haha, and it's a nice approximation :


"1": {
"Altitude": 32500,
"Distance": 51.363231592726649,
"Latitude": -34.01894,
"Longitude": -54.32835,
"Angle": 1

I can do (pi*distance*distance)/360 and get the area of each angle, then sum the 360 calculated areas :)

A friend of mine can help me with the programming part of this, using python for example, to do it offline.

I am thinking how to show this on the web once it's calculated, but don't know much JavaScript, I am reading about the Hook Events now, for example I was thinking everytime I select a Range Plot from the menu, the area is showed below the aircraft list, but well, this is going to be a hard work. :)

fedelosa
Posts: 3
Joined: Sun Feb 12, 2017 4:52 am

Re: Receiver range, just the last xx hours

Postby fedelosa » Tue Feb 14, 2017 10:07 pm

Hi agw, what are the units of the distance in the SavedPlots/RECEIVER.json?

"1": {
"Altitude": 32500,
"Distance": 51.363231592726649,
"Latitude": -34.01894,
"Longitude": -54.32835,
"Angle": 1

Are they nmi? Km? They not change even if I change the units in server config, so I think you use a unique unit internally.


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