Hello list<br>I'm facing for the first time the need of serving a big raster dataset continuum though a Mapserver wms service. The data source, at the moment, is an ArcIms service (this comes for various reasons).<br>I've considered two options to tile, cache and serve it:<br>
<br> - use gdaltindex to use the tileindex functionality of Mapserver<br> - use gdal_wms pointing to a TileCache wms-c service<br><br>In the latter way I've setup the xml configuration file to use the highest resolution level available in the TC cache, and set the maximum serveble bbox. Now, I suppose that the chain is the following:<br>
<br> 1 - mapserver passes the request extent and dimensions to the gdal driver<br> 2 - gdal_wms calculates the tiles needed to fullfill the request at the level set in TileLevel<br> 3 - it turns the "tiled requests" to TC wich verify if they match the tiles in the cache. If ok it give them back to gdal_wms<br>
4 - gdal_wms mosaic the tiles (and clip them to the extent of the MS request?)<br> 5 - Mapserver returns the result<br><br>Is it right? If it is, where is the performance improvement respect to tiling (with gdaltindex) a raster as big as the ensemble of the whole TC tiles at it's highest resolution? I mean, I can have 20x20 tiles cache in TC for my bbox at the maximum level chosen, let's say 5, that is 5120x5120 pixels (standard tiles). Now, if I generate a single image with the same dimensions and then use gdaltindex to break it in tiles and serve them through a tileindex, doesn't I obtain a similar result (in performance terms) as using gdal_wms?<br>
<br>I'm sorry if I haven't been very clear, but I hope you have understood my doubts.<br><br>Thanks a lot for any suggestion,<br>Giovanni<br>