安装geos

gistfile1.txt

Just got it working after 2 hours of tinkering.
For Ubuntu 14.04, libgeos 3.4.2, and RGeo 0.3.20 in Rails 4.2.1:

sudo apt-get -y install libgeos-3.4.2 libgeos-dev libproj0 libproj-dev
sudo ln -s /usr/lib/libgeos-3.4.2.so /usr/lib/libgeos.so
sudo ln -s /usr/lib/libgeos-3.4.2.so /usr/lib/libgeos.so.1
In the Gemfile:

gem 'rgeo', require: false
Good luck!

#remove previous rgeo installation
gem uninstall rgeo

#install GEOS packages
sudo apt-get install libgeos-dev
sudo apt-get install libgeos-3.3.8

#install proj package, I don't need it actually but not sure if it wasn't working because of this
sudo apt-get install proj

#Create a symbolic link named libgeos.so that points to the newly installed version of libgeos
cd /usr/lib
ln -s libgeos-3.3.8.so libgeos.so

#clone the repo of the rails project in other location, Rails apparently insisted on using the old, unlinked to GEOS, version of the gem

#And the reinstall the project's gems
bundle install