.flightlog to .gpx conversion

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.flightlog to .gpx conversion

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adhawkins	adhawkins posted 10/12/2013 6:14:19 PM HOT Topic Details Share Topic
Group: Forum Members Posts: 274, Visits: 2.5K	Hi, Is there any means of doing a 'mass' conversion of .flightlog files to .gpx format? Any plans to produce one? Failing that, any chance the format of the .flightlog file could be documented so that I could consider writing one myself? Cheers Andy
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adhawkins	adhawkins posted 10/14/2013 9:18:19 AM Post Details Share Post
Group: Forum Members Posts: 274, Visits: 2.5K	stevelup (14/10/2013) Have you had a look at the .flightplan file? It's XML and is pretty much self-explanatory. flightlog, not flightplan The flightlog file is CSV, and has a few fields that don't seem obvious. The first line contains a comment, with the start date in it. The first column of subsequent lines is presumably a time stamp since this start time, in milliseconds? Then it's GPS position. After that it's less obvious, but presumably ground speed and height are in there, and the last column seems to be vertical speed perhaps? Anyway, would be good to have them documented if possible. Andy
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adhawkins	adhawkins posted 10/15/2013 9:23:01 PM Post Details Share Post
Group: Forum Members Posts: 274, Visits: 2.5K	Ok, done some digging. There are 6 fields per line, here's what I've managed to guess at so far: Field 1 - A timestamp (presumably milliseconds since the start of the log as per the comment in the first line) Field 2 - GPS co-ordinates Field 3 - ?? Field 4 - Speed (in knots?) Field 5 - Height in feet Field 6 - ?? Would appreciate some sort of indication that I'm on the right track if possible. Andy
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*stevelup*	*stevelup* posted 10/16/2013 8:33:09 AM Post Details Share Post
Group: Moderators Posts: 593, Visits: 4.9K	Field 3 is the heading (a trip from Oaksey to Oaksey started and finished with it reading 23 for me, and the runway is 22) Filed 4 appears to be in kts (my climb out is reading 65-75, cruise 115-120 and approach 55-60 - all of which are correct assuming it was a calm day) Field 5 is definitely in feet (my start and end readings for the above trip are 270 and 272 ft) Field 6 appears to be vertical speed - in that the start of the trip has positive numbers, the end of the trip has negative numbers, and the middle is mostly zero. The null range on this seems sticky - it doesn't report slight deviations, only significant ones. To convert to GPX, all you need are the co-ordinates and altitude - and possibly the timestamp?
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adhawkins	adhawkins posted 10/16/2013 9:09:19 AM Post Details Share Post
Group: Forum Members Posts: 274, Visits: 2.5K	Thanks for that Steve, seems to agree with my findings from reading the file. I've found the GPX spec, and also looked at the GPX files that SkyDemon generates, so should be Ok now to proceed with the conversion. My aim will be to produce a file that's near identical to the one SkyDemon generates when it does the export. Would be nice if Tim could just confirm our findings, particularly in terms of units used. Cheers Andy
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adhawkins	adhawkins posted 10/16/2013 8:42:25 PM Post Details Share Post
Group: Forum Members Posts: 274, Visits: 2.5K	Ok, getting there I think. All looks good, but for some reason my latitude calculations don't quite match up with SkyDemon's, I'm often one or two digits off in the 6th decimal place. I don't think that's significant, but I can't understand why! I've attached 3 files, one .flightlog file which is the source. Then there's a GPX file (the one without ADH in the name) that is the file converted using SkyDemon. Finally another GPX file (with ADH in the name) which is converted using my utility. If you look at the first latitude in the file, in the source file it's: N514241.70 Which is 51 degrees, 42 minutes, 41.7 seconds north. I'm converting this to decimal degrees using: decdeg = deg + mins/60 + secs/3600 and I get 51.711583333333333333333333333333, which I round to 6 decimal places to get 51.711583. However, the measurement in SkyDemon's GPX file is 51.711580. This trend follows throughout the file on the latitude fields, but the longitude fields (converted in exactly the same way) tend to be correct. Anyone offer any suggestions as to what I might be doing wrong? Cheers Andy Attachments (94 nm) Pembrey - Oaksey Park 201309291208.flightlog.csv (565 views, 59.00 KB) 2013-09-29 - Pembrey to Oaksey.gpx (574 views, 187.00 KB) (94 nm) Pembrey - Oaksey Park 201309291208.flightlog-adh.gpx (551 views, 186.00 KB)
	Reply Like 87

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.flightlog to .gpx conversion

adhawkins - 10/12/2013 6:14:19 PM

Have you had a look at the .flightplan file? It's XML and is pretty...

stevelup - 10/14/2013 8:09:13 AM

[quote][b]stevelup (14/10/2013)[/b][hr]Have you had a look at the...

adhawkins - 10/14/2013 9:18:19 AM

Ok, done some digging. There are 6 fields per line, here's what I've...

adhawkins - 10/15/2013 9:23:01 PM

Field 3 is the heading (a trip from Oaksey to Oaksey started and...

stevelup - 10/16/2013 8:33:09 AM

Thanks for that Steve, seems to agree with my findings from reading...

adhawkins - 10/16/2013 9:09:19 AM

Ok, getting there I think. All looks good, but for some reason my...

adhawkins - 10/16/2013 8:42:25 PM

Fields are: Elapsed time (milliseconds) Position Track (degrees...

Tim Dawson - 10/21/2013 3:16:17 PM

Excellent Tim, thanks for confirming that. Andy

adhawkins - 10/22/2013 12:33:57 PM

Returning to this after a holiday with another question. The first...

adhawkins - 11/5/2013 12:43:59 PM

The filename itself should include the start time on old files....

Tim Dawson - 11/5/2013 12:53:38 PM

Ok, seems like I had the right idea then. Finally, where does it get...

adhawkins - 11/6/2013 12:36:01 PM

I can't remember what's in the name tag. Is it a friendly description...

Tim Dawson - 11/7/2013 1:04:22 PM

It's something like 'Kemble to Cranfield'. Ok, I obviously won't be...

adhawkins - 11/8/2013 12:19:01 PM

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