Re: [Mapnik-users] rendering a track

[Dane Springmeyer]

Torsten,

I see a few simple problems and a few less so.
First, your gpx sample files only have a 'wayoints' layer so you need  
to symbolize them with a PointSymbolizer. Currently you are using a  
LineSymbolizer on point data which won't show anything, so try  
something like this for your gpx styles and layer:

<Style name="qwepoint">
    <Rule>
      <PointSymbolizer allow_overlap="true"/>
    </Rule>
</Style>

<Layer name="waypoints" status="on" srs="+init=epsg:4326">
    <StyleName>qwepoint</StyleName>
    <Datasource>
      <Parameter name="type">ogr</Parameter>
      <Parameter name="file">test.gpx</Parameter>
      <Parameter name="layer">waypoints</Parameter>
    </Datasource>
</Layer>

Next, I recommend taking away all Min/Max scaledenominators so that  
this will not get in the way of your testing and you'll see the data  
at any scale.

When I make these changes I get points placed on the map fine using  
nik2img.py:

nik2img.py osm_track.xml image.png --zoom-to-layer waypoints -v

Next, I appears that Mapnik may be loosing some points (perhaps due to  
that unhandled oid error - not sure yet), so try with some sample data  
with at least a few points in the same general location:


<?xml version="1.0" encoding="UTF-8" standalone="no" ?>
<gpx>

  <wpt lat="39.91153" lon="3.05957">
  </wpt>
  <wpt lat="39.91777" lon="3.05418">
  </wpt>
  <wpt lat="39.92417" lon="3.05158">
  </wpt>
  <wpt lat="39.91698" lon="3.05485">
  </wpt>

</gpx>


With this nik2img.py command that creates the attached graphic:

nik2img.py osm_track.xml image.png --zoom-to-layer waypoints -v

<<inline: waypoints.png>>



On Aug 12, 2009, at 2:07 PM, Torsten Mohr wrote:

Hello,

my apologies for sending a too long message first.  I hope the admin  
cancelled
it.

In osm.xml the GPX source file can be inserted (near the end).
When executing "do_track.py", no track is drawn.

Here's the original message:


Hello Dane,

is it a hint on what goes wrong?

No, I think you will need to post a full test case, ideally with a
sample (small) gpx dataset and sample xml styles.

I stripped the files down quite a bit and attached them to this mail.
A guess is that the problem is something really simple, a typo or
similar...

None of the attached GPX files work.  One of them is based on the
example found on Wikipedia.


Best regards,
Torsten.

<osm_track.xml><do_track.py><test.gpx><ttrack.gpx>

_______________________________________________
Mapnik-users mailing list
Mapnik-users@lists.berlios.de
https://lists.berlios.de/mailman/listinfo/mapnik-users