Frequently Asked Questions (FAQ)

Got Questions? We've Got Answers!

  1. What is APRS?
  2. What is APRS Direct?
  3. What browsers do APRS Direct support?
  4. I have a map created in Google My Maps, can I render it on top of APRS Direct?
  5. Can I embed an APRS Direct map on my website?
  6. My latest packet seems to be using different path's depending on what website I look at. Why?
  7. What is a ghost marker?
  8. Can you remove APRS-packets?
  9. Can you tell me how the APRS Direct marker logic works?
 

1. What is APRS?

APRS (Automatic Packet Reporting System) is a digital communications system that uses packet radio to send real time tactical information (on amateur radio frequencies). The APRS network is used by ham radio operators all over the world. Information shared over the APRS network is for example coordinates, altitude, speed, heading, text messages, alerts, announcements, bulletins and weather data. APRS has been developed by Bob Bruninga, callsign WB4APR. More information about APRS can be found at www.aprs.org or at wikipedia.

2. What is APRS Direct?

APRS Direct is a website that brings you global real-time APRS tracking and weather data. Our goal is to bring you a fast and easy-to-use map with the latest APRS activity.

3. What browsers do APRS Direct support?

Our goal is that APRS Direct should work on all broswers that supports websockets (an HTML5 feature). The following browser version (and newer) supports the websocket-protocol. We havn't tested all the following browsers, if you find a problem please mail me.

  • Internet Explorer 10 (released 4/9 2012)
  • Edge 12 (released 30/3 2015)
  • Firefox 11 (released 31/1 2012)
  • Chrome 16 (released 25/10 2012)
  • Safari 7 (released 22/10 2013)
  • Opera 6.1 (released 5/11 2012)
  • iOS Safari 6.1 (released 28/1 2013)
  • Android Browser 4.4 (released 9/12 2013)
  • Blackberry browser 7 (released 1/1 2012)
  • Opera Mobile 12.1 (released 9/10 2012)
  • Chrome 53 for Android (released 8/9 2016)
  • Firefox 49 for Android (released 20/9 2016)
  • IE Mobile 10 (released 20/6 2012)
  • UC Browser 11 (released 17/8 2016)
  • Samsung Internet 4 (released 19/4 2016)

4. I have a map created in Google My Maps, can I render it on top of APRS Direct?

Sure! Follow the following instructions...

  1. Open your map at Google My Maps.
  2. Look at the current URL and try to find a value named mid. Copy that value!
  3. Open up APRS Direct. Add "/mid/{the mid value}" to the end of the APRS Direct URL.
  4. Press Enter!

5. Can I embed an APRS Direct map on my website?

Yes, that is possible. Look at this jsfiddle-example.

  • You will need a Google Maps API key to add as a argument to the Google Maps js URL (like "?key=123"). Google for "Google Maps API key" and you will find out what it is.
  • Do not download the js file https://www.aprsdirect.com/js/trackdirect.min.js. You should use the complete URL (otherwise it may stop working when I change stuff).
  • I'm grateful if you send me an email and tell me about your website.
  • It is also possible to open https://www.aprsdirect.com in an iframe, but if you run a popular website I prefer if you don't do that, since you will be using my "Google Maps API key". Each "Google Maps API key" has a daily page load limit.

6. My latest packet seems to be using different path's depending on what website I look at. Why?

The websites you compare are not collecting packets from the same APRS-IS servers. Each APRS-IS server performes duplicate filtering, and which packet that is considered to be a duplicate may differ depending on which APRS-IS server you ask. The APRS Direct website collects it's packets from our own APRS-IS server, which is connected to a APRS-IS core server.

7. What is a ghost marker?

When we receive a new packet from APRS-IS (we receive about 50-100/second) we need to decide if this packet belongs to a moving station and if the new position is likly. If a position is very far away from the latest position it's more likly that the new position is faulty (probably a bad gps signal). The distance that is likly may differ depending on how fast a station is moving.

If we decide that a new position is unlikly we will consider it to be a ghost-marker. A ghost marker is a marker that is not shown on the map by default, but they can be shown by clicking "Show ghosts markers" in the menu. When a ghost marker is visible it will be a bit transparent, that is how you distinguish a ghost marker from a regular marker.

If we later receive another packet that indicates that the station actually was moving in the same direction as the ghost marker we will convert the ghost marker to a real marker, and include the position in the tail. By doing this we avoid filtering out packets that actually is correct.

8. Can you remove APRS-packets?

Yes we can, but there is a catch (or actually two)...

  • We need to know that you are the owner of that APRS-station (you need to identify yourself somehow).
  • We will delete all or nothing for a specified station, not just some packets.

9. Can you tell me how the APRS Direct marker logic works?

Okay, let me tell you more about our brilliant marker logic :-)

  • It is possible to have several stations with the same name as long as the sender is different (we only allow a sender to take over another sender's object if it looks like they are referring to the same real world object).
  • It's even possible to have several markers with the same name and the same sender as long as they are considered stationary. I do not recommend relying on this feature since APRS is not designed this way (and few other clients will handle it).
  • We have an adaptive speed limit filter and other filters that sorts out packets that has a faulty position.
  • If a moving station sends a packet that is sorted out by our adaptive speed limit filter the packet will be marked as unconfirmed, if we later receive a packet that confirmes that the station is moving in that direction the previous packet will be confirmed.
  • If a station moves in one area and suddently appear in another area the two tails will be connected by a dashed polyline.
  • Packets that has been sorted out by our filters are considered to be ghost-markers, they can be shown by clicking "Show ghosts markers" in the menu.
  • A moving station that reports it's speed and direction will have an animated direction polyline (will be hidden after 15min).
  • The dotted polyline shows the packet transmit path, will be shown when you hover over a marker or a "dotmarker". If a station in the path hasn't sent a position packet in a long time it will show up for some seconds and than disappear again.
  • Note that the time-interval specified in the station info-window (on the map) is how long a station has been on that location without any downtime longer than 24h.
  • Want more information? Mail me!
Initial position
Current position
Ruler
PHG

© 2015-2017 Per Qvarforth SM4WJF
All Rights Reserved
Here you can change how long time a station should be visible.

In this tab we show all APRS packets of any packet type that has been added to the map.

In this tab we show APRS packets of type position that has been added to the map (note that any station may send a position packet).

In this tab we show all APRS packets of type object or item that has been added to the map.

In this tab we show APRS packets of type weather that has been added to the map (note that any station may send a weather packet, not only weather stations).

In this tab we show APRS packets of type direction finding, telemetry, message, query and status that has been added to the map.

 

Select date and time to show map data for (enter time for your locale time zone). The regular time length select box can still be used to select how old data that should be shown (relative to selected date and time).

*Note that the heatmap will still based on data from the latest hour (not the selected date and time).

Date and time:

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APRS Direct


Current time is:


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Station filter


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