[MAPSERVER-USERS] Mapserver bug when generating a tiled map with MapFish

[Daniel Morissette]

Pierre-Benoit,

Unfortunately for you, MapServer has no automated way to deal with 
wrapping coordinates at the date line. If all your data is in the 
[-180,180] range and you request a map for the [180,270] range then 
MapServer doesn't find anything to render and returns a blank map.

You could possibly make a copy of all your data in the [180,540] range 
by adding +360 to all longitude values. I don't know of any tool that 
does that out of the box, but it should be easy to modify ogr2ogr to do 
that for you if you are fluent in C/C++.

Another option might be to look at modifying the MapFish scripts to 
handle the wrapping of coordinates at the +/-180 line and request maps 
from MapServer with the correct extents.

Finally, we could possibly try to handle the wrapping in MapServer... 
you could file a enhancement ticket about that. The addition sounds 
simple at first, but I fear that it may be more involved than it seems.

Daniel

Pierre-Benoit Besse wrote:
> Isn't there anyone to help me with this ?
> 
> 2008/8/4 Faldor <besse.pb at gmail.com <mailto:besse.pb at gmail.com>>
> 
> 
>     Hi all,
> 
>     I use Mapserver with mapfish for the client side to display
>     shapefiles which
>     I generated using ogr2ogr.
> 
>     The problem is when I try to display a tiled layer (mapfish singleTile
>     property set to 'false'). Some tiles are generated by mapserver entirely
>     blank !
> 
>     After a few researches I think it is due to the fact that those
>     tiles are
>     extended "across" the -180°/+180° line.
>     For exemple, here is the imgext property from one of the calls to
>     MapServer
>     which render a blank tile :
>     imgext=178.59375+-1.40625+271.40625+91.40625
> 
>     Do you know of a way to fix this ?
> 
>     Regards,
> 
>     Pierre-Benoît
>     --
>     View this message in context:
>     http://www.nabble.com/Mapserver-bug-when-generating-a-tiled-map-with-MapFish-tp18813432p18813432.html
>     Sent from the Mapserver - User mailing list archive at Nabble.com.
> 
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-- 
Daniel Morissette
http://www.mapgears.com/