Package installation and dependancies - how to prevent installation of existing libraries?

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http://unix.stackexchange.com – Im a relatively new Ubuntu server user, so im learning as i go. I have an issue with a software package im installing (qgis) which has several dependancies one of them being gdal library. Regardless of the installation manager i use (apt, synaptic or aptitude) this package installs gdal version 1.7.3 which is quite outdated (current stable is 1.9.1). I wouldn't have an issue with this if i hadn't already built/compiled the last version of gdal myself (I chose to do so, so i could include some uncommon raster format support). If i type dpkg --list i can see both libraries existing one beside t (HowTos)