Label problems with draggable tiles

[Rob Lee]

Hi,

I have been using some of the 'web front-end' software to mapserver
recently (ka-map, maps.civicactions.net) and have noticed what could
either be considered a bug or a feature of mapserver and wondered what the
rest of the community thought ...

ka-map generates a set of dragable tiles from mapserver via (I believe)
requesting one maptile the size of the viewport and then using the GD
library to cut it into smaller tiles - I believe this is to stop labels
being displayed multiple times (if a set of 4 smaller tiles were requested
from mapserver instead of the one large one) at larger zoom levels e.g. on
a world map when zoomed into a specific country the label would appear on
each of the individual country tiles generated by mapserver.  This can be
seen in action on the map at maps.civicactions.net if you zoom in to a
high enough degree (this application requests four seperate map tiles from
mapserver via javascript).  I guess the reason for this is mapserver was
never envisioned as being used in this way ??

Is this experience also what other used have seen or have I missed a part
of the puzzle - I couldn't see any obvious solution other than the one
used by ka-map.

I believe it would require a modification to mapserver to enable working
with tiles in this fashion ?  I'm not sure what this modification would be
if required - any thoughts ?

Thanks,

Rob Lee