[gdal-dev] ogr2ogr from gpx to postgis - track_fid not maintained for track_points
jratike80
jukka.rahkonen at maanmittauslaitos.fi
Sat Jan 2 13:19:26 PST 2021
Hi,
For my mind the behavior is consistent. FID (in this case named as ogc_fid)
is a unique feature ID and tracks table contains tracks so it is natural
that FID is increasing when more tracks are added - and it must increase or
otherwise the FID is not unique. The track_points table contains points and
FID is unique for each point. If you add more track points the ogc_fid will
increase from the maximum existing ogc_fid value. The track id in the
track_points column in just a normal attribute and it is read directly from
the GPX data.
-Jukka Rahkonen-
Michael Saupe-2 wrote
> Hi Evan,
>
> thank you for the explanation. That makes sense. However, in my opinion
> ogr2ogr behavior is not really consistent in this case: The column ogc_fid
> , which is in fact the track id, is incremented on each gpx file import (
> regardless if you use -update -append or not ).
>
> Michael
>
> Am 02.01.2021 um 14:03 schrieb Even Rouault:
>> Michael,
>>
>> You have a single track in each file, so it is expected that track_fid
>> doesn't
>> change and is set at 0 (as there's no attribute to uniquely identify a
>> track)
>> For what you want to do (that is have distinct track_fid for each file),
>> you'll likely have to use an intermediate postgresql schema, where you
>> would
>> correct the value of track_fid, before merging them together
>>
>> Even
>>
>>> clarification: second table of my points is 'track_points'.
>>>
>>> Also adding my 2 gpx files for reference:
>>>
>>> *file1.gpx:*
>>>
>>> <?xml version="1.0" encoding="UTF-8"?>
>>>
> <gpx version="1.1" xmlns="http://www.topografix.com/GPX/1/1">
>>>
> <metadata>
>>>
> </metadata>
>>>
> <trk>
>>>
> <trkseg>
>>>
> <trkpt lat="49.250324000" lon="8.687196000">
>>>
> <ele>
> 1
> </ele>
>>>
> </trkpt>
>>>
> <trkpt lat="49.250019001" lon="8.687469003">
>>>
> <ele>
> 1
> </ele>
>>>
> </trkpt>
>>>
> <trkpt lat="49.249714001" lon="8.687742003">
>>>
> <ele>
> 1
> </ele>
>>>
> </trkpt>
>>>
> </trkseg>
>>>
> <trkseg>
>>>
> <trkpt lat="49.125652000" lon="8.714194000">
>>>
> <ele>
> 2
> </ele>
>>>
> </trkpt>
>>>
> <trkpt lat="49.125519000" lon="8.714731000">
>>>
> <ele>
> 2
> </ele>
>>>
> </trkpt>
>>>
> <trkpt lat="49.125414000" lon="8.715057001">
>>>
> <ele>
> 2
> </ele>
>>>
> </trkpt>
>>>
> </trkseg>
>>>
> </trk>
>>>
> </gpx>
>>>
>>> *file2.gpx:*
>>>
>>> <?xml version="1.0" encoding="UTF-8"?>
>>>
> <gpx version="1.1" xmlns="http://www.topografix.com/GPX/1/1">
>>>
> <metadata>
>>>
> </metadata>
>>>
> <trk>
>>>
> <trkseg>
>>>
> <trkpt lat="49.11" lon="8.7">
>>>
> <ele>
> 3
> </ele>
>>>
> </trkpt>
>>>
> <trkpt lat="49.12" lon="8.7">
>>>
> <ele>
> 3
> </ele>
>>>
> </trkpt>
>>>
> <trkpt lat="49.13" lon="8.7">
>>>
> <ele>
> 3
> </ele>
>>>
> </trkpt>
>>>
> </trkseg>
>>>
> </trk>
>>>
> </gpx
>>
>>
>>> Am 01.01.2021 um 18:04 schrieb Michael Saupe:
>>>> Hello folks,
>>>>
>>>> I am importing multiple gpx files into a postgis database. The tables
>>>> 'tracks' and 'track_points' are created / updated.
>>>>
>>>> The column track_fid in in the track_points table should be a reference
>>>> to
>>>> the track feature id as documented in
>>>> https://gdal.org/drivers/vector/gpx.html, however it is always zero.
>>>>
>>>> Is this a bug or am I missing something?
>>>>
>>>> Details
>>>>
>>>> I am creating an empty database, then create postgis extension with
>>>> 'CREATE EXTENSION POSTGIS'
>>>>
>>>> I have two simple gpx files ( see attachments )
>>>>
>>>> * file1.gpx - containing 2 track segments - each with 3 track points
>>>> * file2.gpx - containing 1 track segment with 3 track points
>>>>
>>>> I am using commands
>>>>
>>>> ogr2ogr -f PostgreSQL -update -append "PG:dbname=testdb host=localhost
>>>> user=postgres password=xx port=5432" file1.gpx
>>>>
>>>> ogr2ogr -f PostgreSQL -update -append "PG:dbname=testdb host=localhost
>>>> user=postgres password=xx port=5432" file2.gpx
>>>>
>>>> Resulting data in 'tracks'
>>>>
>>>> ogc_fid name cmt desc src link1_href link1_text link1_type
>>>> link2_href link2_text link2_type number type wkb_geometry 1
>> NULL
>>>> NULL NULL NULL NULL NULL NULL NULL NULL NULL NULL
>> NULL ... 2
>>>> NULL NULL NULL NULL NULL NULL NULL NULL NULL NULL
>> NULL NULL
>>>> ...
>>> Resulting data in 'track_points'
>>>
>>> ogc_fid track_fid track_seg_id track_seg_point_id ele time ....
>> other
>>> columns omitted ... 1 0 0 0 1 NULL
>>> 2 0 0 1 1 NULL
>>> 3 0 0 2 1 NULL
>>> 4 0 1 0 2 NULL
>>> 5 0 1 1 2 NULL
>>> 6 0 1 2 2 NULL
>>> 7 0 0 0 3 NULL
>>> 8 0 0 1 3 NULL
>>> 9 0 0 2 3 NULL
>>>
>>>> Expected:
>>>>
>>>> ogc_fid track_fid track_seg_id track_seg_point_id ele time ....
>>>> other columns omitted ... 1 1
>>>>
>>>> 0 0 1 NULL
>>>>
>>>> 2 1
>>>>
>>>> 0 1 1 NULL
>>>>
>>>> 3 1
>>>>
>>>> 0 2 1 NULL
>>>>
>>>> 4 1
>>>>
>>>> 1 0 2 NULL
>>>>
>>>> 5 1
>>>>
>>>> 1 1 2 NULL
>>>>
>>>> 6 1
>>>>
>>>> 1 2 2 NULL
>>>>
>>>> 7 2
>>>>
>>>> 0 0 3 NULL
>>>>
>>>> 8 2
>>>>
>>>> 0 1 3 NULL
>>>>
>>>> 9 2
>>>>
>>>> 0 2 3 NULL
>>>>
>>>> I also tried to omit -update -append, but same result.
>>>>
>>>> Versions:
>>>> * Postgres: "PostgreSQL 12.5 on x86_64-pc-linux-musl, compiled by gcc
>>>> (Alpine 9.3.0) 9.3.0, 64-bit" * Postgis: "POSTGIS="3.0.3 0"
>>>> [EXTENSION]
>>>> PGSQL="120" GEOS="3.8.1-CAPI-1.13.3" PROJ="7.0.1" LIBXML="2.9.10"
>>>> LIBJSON="0.14" LIBPROTOBUF="1.3.3" WAGYU="0.4.3 (Internal)"" * Gdal:
>>>> 3.2.0
>>
>
> _______________________________________________
> gdal-dev mailing list
> gdal-dev at .osgeo
> https://lists.osgeo.org/mailman/listinfo/gdal-dev
--
Sent from: http://osgeo-org.1560.x6.nabble.com/GDAL-Dev-f3742093.html
More information about the gdal-dev
mailing list