Monday, February 2, 2009

APRS path lines

Quite a few of you have asked for some sort of visualization for APRS packet paths. I've just finished a partial implementation of it, and installed it on the production system.

It currently shows the path of a single packet, when you point an APRS station or a track point with the mouse cursor. In the screen shot on the right I had the mouse cursor pointing to the oldest waypoint of OH7FDN, and that position packet was relayed by the digipeater OH7RAA, and forwarded to the APRS-IS by the igate OH7AA.

There are a couple of limitations in this implementation:
  1. It currently only shows the first digipeater found in the path, and the igate.
  2. The digipeater and the igate must be visible on the map (or just outside the visible map area) - you might have to zoom out to make them visible.
  3. The digipeater and the igate must be visible on the map - if you're tracking a single station (you've just searched for a callsign), you'll have to click on "stop tracking".
  4. It currently only works in the real-time view - it doesn't work if you select a day in the past (because it only shows a single station in that mode).
I'll try to improve it in the future, and get rid of these limitations. This is just a start... feedback is welcome!

Features like this always come with a performance penalty. To provide the additional eye candy I'll have to pass on more data to the web browser. It will consume a bit more memory, and make the web browser slow down some more. I certainly hope it's worth it.


Erwin said...

OK, this was one of the functions I was waiting for :)

when this data is available, maybe it's possible to show all the lines to the digi when viewing only one station? almost the same as the map that shows the direct heared stations of a digi. maybe you can give us the choice of viewing the lines or not in this view :
With the lines visible I think it's a better overview.

Erwin ON8AR

9A6AIV said...

OK, maybe it is better way to put that option on right side of window as You put option with PHG circle.
In future try to make difference with know path (like Trace) and unknown path (like Wide)with different color of line.

Gordan 9A6AIV

Steve said...

Excellent feature! Thanks!

VE6SRV said...

Here I thought that I got preferential treatment, but now I know others were asking for the feature as well...

It's looking good. It's a little busy with everyone displayed on the map, it will be more useful as a network analysis tool when you can look at a single station, and look at each position report without the clutter of everyone else on the map.

Multi-hop path viewing would be nice as well... I already found out that there's someone local that is not doing proper callsign substitution using this feature.

Thanks again Hessu! What a great tool!

oh7lzb said...

Yes, there has been quite a few requests for something like this.

I'll continue to improve it, I've already mostly figured out how to make it work for a single tracked station (I'll just have to populate the map with the used digipeaters and igates too), and with multi-digi paths (it'll just eat more browser memory, but memory is cheap, right?).

I'll probably put a button on the right side to enable these.

Anonymous said...

Excellent, I have been hoping for this :-)

Thanks a lot - all your work much appreciated!


LA3QMA said...

wow very nice.

much easier to analyze the network with this visual tool.

antoon said...

Very nice feature, well done !


JA7UDE said...

Cool. Thanks for the nice feature.


vk2him said...

Great work Hessu, as usual!!
Cheers from down under

Chris K6DBG said...

This is a very cool feature, thanks. But it reminds me that the algorithm for "heard direct" and "heard by" is broken in a number of cases.

For example: k6dbg-3 is always heard direct by cdrvly, which igates the packets ... but according to, noone has ever heard k6dbg-3 direct!

Steve said...

I thought this was something I missed before, but just read your blog and it's new.... great feature many thanks...

Anonymous said...

Well I think this function is very useful. Thanks for all you do for APRS.



VE9MHZ/VE3XID said...

Absolutely phenomenal work that just gets better all the time!

Thank you so much!!
Jim in Morrisburg, ON, Canada

oh7lzb said...

Chris, K6DBG: the WIDE1-1,WIDE2-1 case should now be fixed. If there is an intact WIDE1-1 in the beginning of the path (or an intact WIDEx-y where x == y) the first igate in the path will be marked as the "first heard" station.

VE6SRV said...

Being able to track a single station, but show the paths would be great. I was just trying to look at the path of KE7SNS flying over Seattle. It's easy to see his path when he's the only one on the screen, but when you pull up 24 hours of history on all of Puget Sound, you get a pretty big mess.

By populating the tracked station map with digipeaters and i-gates, you would be able to show the track. I just wonder if people would have an issue with having other stations on the screen when they just asked for a specific station. I think if you go with a button to enable it like the PHG option, you could keep everyone happy. Have it as a user toggled option on the main tracking page as well as on the single station page.

Any way you implement it, having the capability to see one station's historical track, and visualization of the paths used is a big bonus.