Hi,

Best way I have found so far is to use Mapserver itself. For the whole 
rasterset it goes very easily by using tileindex as raster input, mapfile 
extents taken from the tileindex shapefile with ogrinfo,GeoTIFF as 
outputformat, some reasonable image size, and then asking for the whole layer 
from Mapserver. I think in your case it would be good to have one more zoom 
level in between, and for that you would need to add BBOX parameter to your 
request. When the site is covered by a suitable number of tiles they can be 
combined with another tileindex. I don't remember any problem in creating 
subsampled images this way, but of cause it takes some time and server timeout 
value must be set accordingly.

By the way, I suppose many Mapserver users would benefit if someone someday 
should make a simple semiautomatic application for performing this common task. 
It might for example show the tileindex shapefile as vector layer with full 
extents to start with, and then ask the user to give the number of rows and 
columns and size of the resulting images as inputs before splitting the raster 
layer to new tiles.

I have also used GDAL (by using GDAL .vrt virtual format as input) and 
commercial software (mosaic utility of ERDAS Imagine) but I prefer Mapserver 
because it is fast and not too tricky to use even when editing the BBOX 
parameters manually. For more automation I use to collect the Mapserver 
requests to batch file.

Regards,

-Jukka Rahkonen-



-----Alkuperäinen viesti-----
Lähettäjä: UMN MapServer Users List [mailto:[EMAIL PROTECTED] Puolesta Tormod 
Spigseth
Lähetetty: 24. heinäkuuta 2006 10:53
Vastaanottaja: [email protected]
Aihe: [UMN_MAPSERVER-USERS] Generating raster overview to separate rasterset.

I have a 240GB aerial rasterset in 4000 tiles, any idea how i can generate 
separate raster sets for higher zoomlevels?

gdaladdo will still require mapserver to load 4000 files.

--
Tormod Spigseth
ByteX / Oxygen
[EMAIL PROTECTED]

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