我正在尝试在 Ubuntu 15.10 上使用 aptitude 安装 postgis，但虚拟包出现问题，导致安装失败。
me@laptop:~$ sudo aptitude install postgis
The following NEW packages will be installed:
libgdal1{ab} libgeos-3.3.3{a} libgeos-c1{a} libgif4{a} libhdf4-0-alt{a} libjson0{a} liblwgeom-2.1.8{ab} libmysqlclient18{a} libodbc1{a} libogdi3.2{a} odbcinst{a} odbcinst1debian2{a} postgis postgis-doc{a}
postgresql-9.4-postgis-2.1{ab}
0 packages upgraded, 15 newly installed, 0 to remove and 5 not upgraded.
Need to get 11.9 MB of archives. After unpacking 31.6 MB will be used.
The following packages have unmet dependencies:
postgresql-9.4-postgis-2.1 : Depends: libproj0 which is a virtual package and is not provided by any available package.
liblwgeom-2.1.8 : Depends: libproj0 which is a virtual package and is not provided by any available package.
libgdal1 : Depends: libarmadillo2 (>= 2.4.2) which is a virtual package and is not provided by any available package.
Depends: libdap11 which is a virtual package and is not provided by any available package.
Depends: libdapclient3 which is a virtual package and is not provided by any available package.
Depends: libepsilon0 which is a virtual package and is not provided by any available package.
Depends: libhdf5-serial-1.8.4 which is a virtual package and is not provided by any available package.
or
libhdf5-1.8.4 which is a virtual package and is not provided by any available package.
Depends: libnetcdf6 which is a virtual package and is not provided by any available package.
Depends: libpoppler19 which is a virtual package and is not provided by any available package.
Depends: libproj0 which is a virtual package and is not provided by any available package.
Depends: libspatialite3 (>= 2.4.0~rc2) which is a virtual package and is not provided by any available package.
Depends: libxerces-c28 which is a virtual package and is not provided by any available package.
我如何安装虚拟包（如）libproj0，以便可以进行postgis设置？