Wednesday, September 3, 2008

Digi/igate coverage maps

Last night I finished implementing APRS igate and digipeater coverage maps. They come in two flavors (examples from the San Francisco area):

- A 'heard directly' map:, showing packets which have been (supposedly) heard first by the given igate or APRS digipeater. This map can occasionally show some extra coverage if there are digipeaters with no callsign prepending in the area, but I'm trying my best to catch those. If there is good direct receive coverage by one more igates, those will "eat away" the displayed coverage of the digipeaters in the same area, since the digipeated packets will be filtered as duplicates on the APRS-IS.

- A 'passed packets to the Internet' map: This display shows packets which have been gated to the APRS-IS by the selected igate. This gives a rough idea of the service area of the igate, together with the surrounding digipeaters.

The statistics are currently calculated over the last 48 hours. Links to these are only on the info pages (if applicable), but I'll try to add them in the info balloons on the map. The data was already in the database, I just had to add a single index and implement the user interface. As usual, there are a few new strings to be translated.

The 'heard' map could be useful for fine-tuning the PHG information transmitted by a digipeater.


KF4GTA said...

This is awesome. Great job on all your hard work.

VE6SRV said...

Nice! I was thinking about asking for something like this. Great implementation. About the only extra would be to have a longer history, that would give a better idea of the coverage. 48 hours in our low activity area shows only a small portion of the coverage, but longer history means more memory... I can live with this!

oh7lzb said...

Yeah - I would like to have a longer history range, for the same reason, there are some pretty quiet areas here, too.

An extra day of history here costs me about 140 Mbytes of memory on each of the servers, as I need to keep the points in memory. I already increased the in-memory history range from 24 to 48 hours for this report to have a significantly better coverage.

Alternatively, I could summarize the data while it comes in, and store only the data needed for the report, which would reduce the memory footprint, but that would (roughly) mean an extra database transaction per incoming position packet. Since the summarizing-on-demand (when you load the report) in the current implementation happens very quickly (typically some 0.01 seconds), I think it's currently more cost effective to do it this way.

I'll have to keep an eye on the memory consumption, but I'll try to make the history longer. Later!

vk2him said...

This is great Hessu, can I suggest an option to change the color of the plots as red tends to blend with the roads on my map background .. bright green works well :-) .. cheers Ian vk2him

SW2HUI said...

Greek translation updated. I noticed that:

"status/search_question - master revision 1%@beacons/search_question%"

is still there ..

K2DSL said...

Fantastic site and fantastic features. Maybe this is buried somewhere, but is there a way to see, based on zip/location all the stations which are gating anything to the internet? Using the example in the original post, put in San Jose, CA and it shows a map point for W6DTW and then other stations which are passing RF traffic to the internet?

oh7lzb said...

VK2HIM: Yes, I'll consider that. I should make a "switch track colours" tool, too.

SW2HUI: Thanks. I'll try to hide that one.

K2DSL: Currently, no. I should add some other filtering options too, I have some ideas on how to do that. Maybe next month...

I'm currently working on a couple other projects, too: the OH7RDA APRS digipeater on 144.8 in Kuopio (should go and install it on the site in a week), and the OH7RAA 2M repeater's logic board (PIC based). They're taking some of my spare time away from, but it's nice to do some hardware stuff for a change. I'll post some photos of those later.

SQ6NTI said...

Polish translation in progress.
I think "more intense red" will look better than "darker shade of red". Just a suggestion.

oh7lzb said...

sq6nti: Thank you - I just recompiled the languages after your modifications.

Maybe "more intense colour" instead of "red" would be in place, if I get around to doing the colour switching suggested earlier.

SQ6NTI said...

Yes, certainly "colour", or possibly "color" in US version.

oh7lzb said...

Localisation is an interesting field, and I've always greatly enjoyed good old-style British pronunciation in, say, Jeeves & Wooster.

But I don't quite feel like starting to maintain separate UK and US versions right now. :) Maybe later, if we can find a couple of British and US users with very good language skills, and who are motivated enough (read: too annoyed by my mixed language).

co149 said...

Awesome feature! What determines the borders of the squares? They look like half-x-half of a grid square (like CN87un00 - CN87un55) but they don't seem to line up.


Sparqi said...

Love the site. Thanks for using my iGate as the example! Now I'm famous hi hi hi.


David W6DTW

oh7lzb said...

sparqi: I just had to pick a random igate, as I didn't want to use one of our own all the time. You have a very well-written blog!

oh7lzb said...

co149: I've just altered the square calculation to actually make them square everywhere. The width and height of each block is 2 kilometers (1.243 miles). The data is summarized using the modulo function, dividing the latitude and longitude to 2x2km blocks.

Sparqi said...

Thanks Heikki!



kc5ffq said...

Outstanding feature, how do you get an igate included? we have 2 igates in our area not included in this new feature.

VE6SRV said...

Getting an i-gate included is pretty easy, put it on the air, and connect it to the APRS-IS stream. If you have it set up properly and it gates anything to the APRS-IS stream, it will show up on

oh7lzb said...

Yeah, they should be shown without any extra steps. What are their callsigns?

kc5ffq said...

KC5FFQ-5 & K5BAR-5 Located in Abilene, Tx. The igates have been up for some time but we are still working on proper settings so they are working together.

VE6SRV said... and both show up and have stations that they have gated to the APRS-IS as well as heard locally. Have a look.


kc5ffq said...

Great! I was not aware of that feature for each individual site.
Now, how do I get our stations included with the coverage colored bubble when that option is selected?

VE6SRV said...

If you are talking about dig/igate coverage maps, which is what this blog post and set of comments is about, go to the links I posted above.

However, if you are talking about the PHG circles which draw when you press the button on the upper right with the red and blue "circle" in it, that is a different subject.

Include PHG data in your outgoing packets, and you will "be included". You have to send the data so the site can plot your information.

oh7lzb said...

kc5ffq: Just a bit more clarification to get you in the right direction. The PHG data goes in the 'comment' field of the transmitted position packets. You can figure out the right comment field contents using a
PHG calculator.

If you're having trouble getting your PHG data shown, check out the raw packets of a digipeater which shows the PHG circle, and compare them with your own raw packets, and try to make yours similar to the ones which are working. The methods to configure the comment text depend on the software used.

kc5ffq said...

Thank you both for you help. We are now setup and running. Now we will start looking into proper settings for both igates to work together. Hope I can contact you for additional help if needed.

Jim said...

"The 'heard' map could be useful for fine-tuning the PHG information transmitted by a digipeater."

First, I thank you. I'm a noob and still learning the powerful capabilities of this site.

PHG is an indicator of a stations' transmitter, no?

What I would like to see is the 'Stations which heard W3YA-1 directly on radio' data shown visually on the map, with station ID's and possibly colors for the # of packets.

Since we can end up in Canada, I think our PHG circle might be a little conservative?

Thanks for your attention to this.