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mendhak / gpslogger

:satellite: Lightweight GPS Logging Application For Android.
https://gpslogger.app
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gpx(time); hdop #204

Closed szymon1013 closed 10 years ago

szymon1013 commented 10 years ago

HDOP is probably incorrect (in gpx file value is seems to low). Time in element gpx is illegal. documentation gpx http://www.topografix.com/gpx/1/1/#type_trksegType

mendhak commented 10 years ago

It's GPX 1.0 instead of 1.1 (more data, compatibility/commonality) so the time should be OK.

Regarding HDOP, it is simply estimated. Getting it properly would be a bit complicated as the NMEA listener must be running at the same time - in turn meaning the other location coordinates and values must also come from the NMEA or there would be a mismatch. It's also a matter of finding time but that's quite scarce these days.

szymon1013 commented 10 years ago

So this divide (loc.getAccuracy() / 5) is correct ? I'm asking becouse I want to use this value in path simplification (douglas-peucker) and in other app OsmAnd hdop value seems be more resonable. BTW Reuman – Witkan simplication in your app would be great.

mendhak commented 10 years ago

Ah if you are getting better values in OsmAnd you are probably better off using that one. The divide-by-5 is just a rough estimate so it's not really accurate more like a ballpark figure.

mendhak commented 10 years ago

HDOP is now being read from the NMEA listener; if at the time of logging a point an HDOP, PDOP and VDOP are available, it will be logged to the file.