[Mapserver-users] Tileindex questions.

[Bob Basques]

Howard Mark wrote:

>Ed,
>
>A very good point. Let me interject one idea that I've used that really speeds up performance. 
>I use a tile index and check performance by zooming in to about 1:20K. Then I zoom out until performance drops. 
>I create a new tile grid shapefile using that map extent as the size of one tile. I tile the entire map area (in my case the world). 
>I create a new aggregate image layer using calls to the map server to generate an image for each new tile.
>I repeat this process until I have good performance at any scale. I then tune the scales in the map file to match the layers.
>This "pyramid" scheme is used in several map server products.
>Granted 528 images are not that many - but displaying all at once takes a bit of time.
>I've created a world mosaic from 360,000 images that displays at any scale in no more than 4 seconds.
>
>Mark
>
>  
>
I've actually set something like that up already myself as well.  (Not 
Using MapServer)

This Proof of concept (Multiple resolution layers), works very nicely 
for this DHTML setup to access tiled data directly.

http://pwultra5.ci.stpaul.mn.us/cgi-bin/drill/req.08.pl
(Click in the image, then Ctrl-click after that, no zoomout I'm afraid, 
but you get a measure of the performance, this is a bit slow becuase it 
pulla bunch of different images for each layer and does the clipping of 
things in the browser.  But it doesn't have the overhaed of any Server 
being needed.)

I'm moving this to Mapserver in the next couple of weeks, so the images 
will be single for each DHTM layer.

See here (latest tests with MapServer, the whole city is already done 
for each map below)

http://pwultra5.ci.stpaul.mn.us/cgi-bin/url3.pl?mapext=550000+140000+555000+145000&mapsize=1000+1000&map=/var/www/html/raster/horizons.map&mode=map
http://pwultra5.ci.stpaul.mn.us/cgi-bin/url3.pl?mapext=550000+140000+555000+145000&mapsize=1000+1000&map=/var/www/html/raster/citipix.map&mode=map
http://pwultra5.ci.stpaul.mn.us/cgi-bin/url3.pl?mapext=550000+140000+555000+145000&mapsize=1000+1000&map=/var/www/html/raster/rswcd_1985.map&mode=map
http://pwultra5.ci.stpaul.mn.us/cgi-bin/url3.pl?mapext=550000+140000+555000+145000&mapsize=1000+1000&map=/var/www/html/raster/rswcd_1974.map&mode=map
http://pwultra5.ci.stpaul.mn.us/cgi-bin/url3.pl?mapext=550000+140000+555000+145000&mapsize=1000+1000&map=/var/www/html/raster/rswcd_1953.map&mode=map
http://pwultra5.ci.stpaul.mn.us/cgi-bin/url3.pl?mapext=550000+140000+555000+145000&mapsize=1000+1000&map=/var/www/html/raster/rswcd_1940.map&mode=map

Count me as a confirmed Mapserver Fan.  Now if I can just get it to read 
AutoCAD files . . . .

bobb