安装Qgis时出现依赖性问题：我正在Ubuntu 16.04上安装qgis 2.14
sudo apt-get install qgis python-qgis qgis-plugin-grass
Reading package lists... Done
Building dependency tree
Reading state information... Done
python-qgis is already the newest version (1:2.18.9+24xenial).
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:
The following packages have unmet dependencies:
qgis : Depends: python-qgis (= 1:2.14.15+24xenial) but 1:2.18.9+24xenial is to be installed
Depends: qgis-providers (= 1:2.14.15+24xenial) but 1:2.18.9+24xenial is to be installed
Depends: qgis-common (= 1:2.14.15+24xenial) but 1:2.18.9+24xenial is to be installed
Recommends: qgis-plugin-globe but it is not going to be installed
qgis-plugin-grass : Depends: qgis-plugin-grass-common (= 1:2.14.15+24xenial) but 1:2.18.9+24xenial is to be installed
Depends: qgis-provider-grass (= 1:2.14.15+24xenial) but 1:2.18.9+24xenial is to be installed
E: Unable to correct problems, you have held broken packages.
sudo apt purge *qgis*
然后重新安装。它可能会帮助您。