[Tilecache] Re solutions issues

[Christopher Schmidt]

On Thu, Nov 20, 2008 at 02:28:30PM -0500, Yves Moisan wrote:
> Answering to self and asking some questions :
> 
> 
> 
> > url=http://myserver:8292/cgi-bin/mapserv.exe
> 
> for MapServer, this line needs ...mapserv.exe?map=/path/to/mapfile.map
> (thanx Alexandre offline).  After that, I had the usual interlaced PNG
> error and tweaked the mapfile to get TC to work.  I found my TC was
> pretty slow so in a bid to up performances, I switched to jpeg.  Even
> though tile size (bytewise) diminished significantly, I still find it is
> pretty slow.  My nontiled version of the layer (an Ikonos GeoTIFF image
> reduced to 8 bits and then internally tiles using gdal_translate and
> then with an overview using gdaladdo) is faster to render than my tiled
> version, which is using the same internally tiled addo GeoTIFF image.  I
> have a feeling the number of gets is so great that network issues hinder
> TC performance.  Has anyone experienced that ?

Doubtful. Are you using TileCache CGI? If so, that's your problem. 

> As an aside, we are transitioning from a PHP Mapscript application,
> namely Pmapper, to Openlayers.  We still experience a faster image load
> with Pmapper even though it uses the slower Mapscript.  Either it does a
> better job at querying MapServer for the right portion of the GeoTIFF
> image or it is just plain more efficient.

If you're using CGI, it's the latter. Switch to mod_python. (Comparing
CGI to mod_php is unfair.)

Regards,
-- 
Christopher Schmidt
MetaCarta