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gpx files

Created by Jman Jman  > 9 months ago, 13 Nov 2007
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Jman
Jman

VIC

881 posts

13 Nov 2007 10:11pm
Hi Guys
After I delete some invalid data in realspeed I save it as a gpx file, the problem is when I try to open up the saved gpx file realspeed 1.92 seems to lock up and I have to end task. What am I doing wrong?
mineral1
mineral1

WA

4564 posts

13 Nov 2007 8:21pm
Email file to TIMEMACHINE (Mal)
Had issue with mine also. He did a patch for me.
He will answer ASAP
Mineral
firiebob
firiebob

WA

3177 posts

13 Nov 2007 9:11pm
For interest, my original files are SBN and they open quickly. But when I load a saved GPX, I thought it was locking up RealSpeed, couldn't work it out. Then I found if I just left it to do what it does, it finally loads, takes awhile.

May be, or may be not be the same
decrepit
decrepit

WA

12802 posts

13 Nov 2007 9:25pm
I agree with firebob, realspeed takes ages to load a gpx file, seems to be doing nothing, then all of a sudden you get the normal activity on the bottom line, telling you which division it's processing. Hardy also thought gpx was locking up, but when he was patient it all worked.

I'm not sure, but I suspect realspeed has to convert the format back to whatever it uses, although it doesn't take long to save the file.
mathew
mathew

QLD

2142 posts

14 Nov 2007 12:11am
The problem with loading GPX files isn't directly related to RealSpeed, but rather to the use of a library which reads the XML data; once the library is finished loading the data, it hands it over to RS which is why you see the statusbar light up.
firiebob
firiebob

WA

3177 posts

13 Nov 2007 11:24pm
OK Mathew, now I have to ask, what library ?

Thanks in advance & goodnight
mathew
mathew

QLD

2142 posts

14 Nov 2007 11:45am
[}:)]

The GPX file format is an XML document which uses a specific document-type-definition which spells out what elements are valid and their corresponding attributes. (XML documents are a bit like web pages, with its angle-brackets and keywords.)

Software libraries exists for reading/validating that the XML file meets the DTD specification; RealSpeed uses one of those libraries (I think it uses "Expat"). Each library has its own technique for reading/processing the XML file, but to simplify the explanation: the library reads the file, checking for validity, eventually handing the 'valid' data to RealSpeed.

... not really a good explanation, but hey, Google is your friend.
decrepit
decrepit

WA

12802 posts

14 Nov 2007 2:08pm
So my "feeling" of what was going on wasn't too far off the mark.
mikey100
mikey100

QLD

1105 posts

14 Nov 2007 5:14pm
Dont really understand all the technical stuff, but my garmin files (gpx)can only be read by an older (1.8..) version of realspeed, not the newer 1.9.. version. Get an older version!
mathew
mathew

QLD

2142 posts

14 Nov 2007 6:22pm
Select to expand quote
mikey100 said...

Dont really understand all the technical stuff, but my garmin files (gpx)can only be read by an older (1.8..) version of realspeed, not the newer 1.9.. version. Get an older version!


Make sure you get the latest version (1.920 or even 1.919) - it fixes some GPX display issues.
Jman
Jman

VIC

881 posts

14 Nov 2007 10:51pm
Ok,the gpx files will load it just takes about 10 min on my old machine
I'll just have to crack open a can while waiting that should help
TimeMachine
TimeMachine

89 posts

14 Nov 2007 9:04pm
Guys, I gotta agree with you that RealSpeed is slow to read GPX files. Mat is right on the money that RealSpeed is using the Microsoft XML parser to read the XML, which is the cause of the trouble. The fact that the parser validates the data sounds like a plausable excuse, but it should never take that long. The library is just really slow.

I think Yann gave up and wrote his own XML parser for GPSAR to improve the performance and I really need to do the same. I'll look at it soon because shortly we will all be using 5 and 10hz GPS units and the huge number of trackpoints in each file will become a major pain in the arse. At 10hz, one hour of recording is 36,000 points... This is why I was so keen to support the SBP format which is really compact and super fast to load and save.
firiebob
firiebob

WA

3177 posts

14 Nov 2007 10:12pm
Thanks mobs Mal for the heads up.

My Navi records to the card using SBN files, I'm guessing they are same or similar to SBP ?
Anyway, nice and fast, no problem.

If you don't have a Navi Jman, do as you say and crack a can, who cares then hey

Thank you mathew, sorta makes sense now mate

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