Am Thu, 07 Aug 2008 11:15:02 +0200 schrieb Ric S:
> Hi folks,
>
> I have successfully setup mapnik. Generating a map already works.
> Now I would like to draw gps points into the map, I was searching the
> net for a few hours to get some info, unfortunately
> I still have now clue yet how this can be done with mapnik.
> I assume I have to create a layer and add points to it. I could not
> find an example how to draw points.
>
> I would like to set gps points in my map. Could you please show me
> how to add a single gps point to this map/layer. The code from
> generate_image which I used:
> ...
> z = 10
> imgx = 100 * z
> imgy = 100 * z
>
> m = Map(imgx,imgy)
> load_map(m,mapfile)
> prj = Projection("+proj=merc +a=6378137 +b=6378137 +lat_ts=0.0
> +lon_0=0.0 +x_0=0.0 +y_0=0 +k=1.0 +units=m [EMAIL PROTECTED] +no_defs
> +over") c0 = prj.forward(Coord(ll[0],ll[1]))
> c1 = prj.forward(Coord(ll[2],ll[3]))
> bbox = Envelope(c0.x,c0.y,c1.x,c1.y)
> m.zoom_to_box(bbox)
> im = Image(imgx,imgy)
> render(m, im)
> view = im.view(0,0,imgx,imgy) # x,y,width,height
> view.save(map_uri,'png')
I've done that some time ago. Worked well. But then I deactivated the
code for some reason. Not sure if it works at the moment:
void MapnikSource::insertDataPoint (double x, double y, const char *key, const
char *value, const char* layer)
{
/*Layer lyr (layer);
datasource_ptr ds (new mapnik::memory_datasource);
feature_ptr f (feature_factory::create (keyID));
geometry_ptr point (new point_impl (-1));
point->move_to (x, y);
f->set_geometry(point);
transcoder tr ("utf-8");
(*f)[key] = tr.transcode (value);
if (ds)
{
mapnik::memory_datasource *mem = dynamic_cast
<mapnik::memory_datasource*> (ds.get ());
if (mem) // check if cast is ok!
{
// do something with memory_datasource e.g. push some
features
mem->push(mapnik::feature_ptr(new mapnik::Feature(-1)));
mem->push (f);
}
}
lyr.set_srs ("+proj=latlong +datum=WGS84");
lyr.add_style ("enigator");
lyr.set_datasource(mapnik::datasource_ptr(ds));
map->addLayer (lyr);
keyID++;*/
}
This is how I called it:
m_mapnikSource.insertDataPoint (x, y, "enigator", "wptred", "enigator");
This is the reference in the XML file:
<Style name="enigator">
<Rule>
<MaxScaleDenominator>50000</MaxScaleDenominator>
<Filter>[enigator]='wptred'</Filter>
<PointSymbolizer
file="/home/andreas/src/svn/enigator/trunk/data/symbols/wptred.png" type="png"
width="32" height="32" />
</Rule>
</Style>
Search the history of this list with my name and around 10-12 month ago or so.
Maybe this helps you...
regards
Andreas
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