Tuesday, April 22, 2008

Imperial and nautical units for Google Earth KML APRS view

The unit configuration selected in Options now applies to the Google Earth Network Link, which is produced when you click on the Google Earth KML link on aprs.fi. Fahrenheit temperatures are supported, too. US users should get Imperial units and Fahrenheit temperatures by default, UK users should get Imperial units and Celsius temperatures.

If you have installed the aprs.fi Google Earth APRS link before, and wish to change your units configuration, please do the following:
  1. Delete your existing link from Google Earth by right-clicking the top-level "APRS:" link and selecting Delete (not Delete Contents)
  2. Select your units configuration in the aprs.fi Options window
  3. Open a new KML link using the Google Earth KML link on aprs.fi
This way the new units configuration will be copied over to the Google Earth KML link. When you change your configuration again in the Options, you'll need to delete the existing link in Google Earth and open up a new one from aprs.fi.

Some UTF-8 character encoding issues were also fixed in the KML interface.

Saturday, April 19, 2008

Little enhancements

Joe, K7JD has been pointing out (for quite a while now) that there's more accuracy in the speed and altitude formats used on aprs.fi than would be appropriate. I've removed the decimal digit from the speed and altitude formatting functions now, since there isn't that much accuracy in the source data anyway.

Max, KG4PID pointed out that the info balloons on the map show really old weather data for stations which have sent even just a couple of WX packets sometime in the last summer. I made a small change to make it only show WX data updated within the past hour.

I've also compressed the big javascript files, so that they will download faster, especially on mobile devices. This process can also be called optimizing, since they will run slightly faster on many browsers, and obfuscating, since they're now much harder to read. Sorry about that.

Tuesday, April 8, 2008

Firefox 3 beta not working with aprs.fi

Zach Sadecki was the first to let me know that the Firefox 3 beta has some trouble with aprs.fi. I did some testing, and sure enough, it fails sooner or later with some JavaScript errors being printed in the Error Console. It has something to do with the decoding of the XML in the AJAX XMLHttpRequest responses.

I verified the site still works with Firefox 1, Firefox 2, MSIE 6 and 7, Konqueror and Safari, and went to report a bug in the bug tracking system of the Mozilla project, only to find that Zach had already issued Bug 425586 – javascript doesn't run that works fine on firefox 2.0. So, after a bit more testing, I added a comment there. This seems like a FF3 bug to me, one that is a bit hard to work around in aprs.fi code.

Zack also pointed out that the Gecko-based Epiphany browser suffers from the same problem.

It might be useful if you'd happen to find another ajax-based site which suffers from exactly the same problem. Please, drop a comment if you do.

Update: I've installed a workaround for this problem, and it seems to work. I'm re-parsing the AJAX XML using the GXml API.

Thursday, April 3, 2008

APRS bulletin group browsing

Tonight I added a small feature to the APRS bulletin board. It can now show bulletins belonging to a specific group, for example MAREA, EI or EVENT.

Directing bulletins to specific interest groups could make the bulletin board scale up a little bit, currently it is filled by just the same old web site and BBS/DX cluster advertisements.

A few days ago I did some programming on the hamdr APRS tracker firmware. It was fun to program C on a 16-bit embedded platform for a change. Tuned it's telemetry transmission a little bit, and added TLL NMEA waypoint sentence support.