[Openstreetmap] major db refactoring and GPS data

[Andy Robinson]

By default, gpsbable seems to spew out those extra lines of data when
standard NMEA sentences are converted to gpx. It's useful to see the
dilution and satellite data before you upload the file to clean out poor
quality data by hand. You could argue the same could be achieved by the OSM
import code. Either way once the process has been done there isn't really
any need for those columns. As you say, most of the non NMEA retail devices
are not set to use NMEA by default anyway, certainly my ETREX was not
providing me with that data through the Garmin interface.

I'd go for dumping the existing data already imported but consider an import
mask in the code to weed out erroneous import data when dilution and
satellite info is available in the gpx file.

Andy Robinson
Andy_J_Robinson at blueyonder.co.uk 

>-----Original Message-----
>From: openstreetmap-bounces at vr.ucl.ac.uk [mailto:openstreetmap-
>bounces at vr.ucl.ac.uk] On Behalf Of SteveC
>Sent: 17 January 2006 16:17
>To: openstreetmap at vr.ucl.ac.uk
>Subject: [Openstreetmap] major db refactoring and GPS data
>
>Hello,
>
>I'm refactoring the database which will require some downtime perhaps
>tomorrow night again. This is in preperation for getting streets, areas
>and curved street segments done. As well as for a move to postgres at
>some point.
>
>I'm removing all the dead tables, renaming tables and columns to
>sensible names and changing all the timestamp like fields from using
>unix time to SQL datetime fields.
>
>This is quite a chunk of work, with changes all over the place in the
>codebase.
>
>I've noticed in the gps data table we have fields for:
>
>* horizontal dilution
>* vertical dilution
>* number of visible satellites
>* quality
>
>And none of them are used. Indeed, it's hard to find retail GPS
>receivers that even give that data in their output through gpsbabel.
>Granted you can get these things out of a USB GPS etc.
>
>So given we have 14 or 15 million rows with 4 unused columns and I don't
>recall anyone really wanting that data parsed and stored... should we
>keep it?
>
>have fun,
>
>SteveC steve at asklater.com http://www.asklater.com/steve/
>
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