Hi,
One more thing, save some more space and compress the overviews as well. It is documented in http://www.gdal.org/gdaladdo.html
If image itself is compressed with DEFLATE, use --config COMPRESS_OVERVIEW DEFLATE.
-Jukka Rahkonen-
···
Jonathan Moules wrote:
You can simplify your process because you already use –a_srs parameter (“assign spatial reference system”) . Therefore it should not be necessary to create all those .prj files at all.
Gdaladdo with resolution 1 does not make sense because it means creating an overview with original resolution. I hope that gdaladdo quitly skips it, otherwise you are getting all too large files.
Speaking from experience (I did this myself long ago before understanding) - gdaladdo happily creates the pyramids at level 1. So you end up with a file that’s double it’s original size!
It is also good to know that gdaladdo –clean does not remove old overviews physically and filesize will not shrink.
Yup. It just removes the links to the overviews. I found that out the hard way too. 
The lines in my last email have what seems to be the optimal - everything is inside a single file and the result is optimised for GeoServer.
I’ve tested now it on the OS 50k for the entire country - there’s no need to split into two files and image mosaic. The resultant file is only about 2.5GB pre overviews (which usually add another 30%). So just loading that file as a regular single GeoTiff should be fine.
Cheers,
Jonathan
This transmission is intended for the named addressee(s) only and may contain confidential, sensitive or personal information and should be handled accordingly. Unless you are the named addressee (or authorised to receive it for the addressee) you may not copy or use it, or disclose it to anyone else. If you have received this transmission in error please notify the sender immediately. All email traffic sent to or from us, including without limitation all GCSX traffic, may be subject to recording and/or monitoring in accordance with relevant legislation.