[ka-Map-users] variable substitution

Tim Schaub tim at commenspace.org
Tue Apr 4 13:53:49 EDT 2006

If anybody is interested in having data, connection strings, filters, or
class expressions that are defined on the client side of a ka-Map
application, I've added the ability to do variable replacement (a la
MapServer CGI variable substitution).
See the MapServer docs for how this works in your mapfile:
For how this works in your ka-Map setup, I've added some documentation
This is the fourth option for the "tile_source" layer metadata option:
"nocache."  Note that variable replacement (substitution) only works
when you specify "tile_source" "nocache" for one of your layers.  Also
note that this option does not have the benefits of drawing a large
metatile (to avoid duplicate labels).  
If you are feeling adventurous and decide to try this out, you'll want
to be aware of the $tileBuffer variable in tile_nocache.php.  This value
is set to avoid drawing partial symbols at the edge of tiles.  It should
be greater than or equal to half of your larges symbol size in pixels
(so a point on the edge of a tile is fully drawn within the buffer).  If
this is getting used, it may make sense to move this setting to
config.php at some point in the future.

If you use this and have trouble, please add any comments (suspected
bugs) to http://bugzilla.maptools.org/show_bug.cgi?id=1349

Tim Schaub
CommEn Space

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