I am trying to install Cartopy on Ubuntu and need to install proj v8.0.0 binaries for Cartopy. However when I try to apt-get install proj-bin I can only get proj v6.3.1. How do I install the latest (or at least v8.0.0) proj for cartopy?

I'm answering my own question here partly to help others with this problem, and partly as an archive for myself so I know how to fix this issue if I come across it again. I spent quite a while trying to figure it out, and wrote detailed instructions, so see below:

Installing cartopy is a huge pain, and I've found using conda to be a very bad idea (it has bricked itself and python along with it multiple times for me)

THIS INSTALLATION IS FOR LINUX.

Step 0. Update apt:

apt update

Step 1. Install GEOS:

Run the following command to install GEOS:

apt-get install libgeos-dev

In case that doesn't do it, install all files with this:

apt-get install libgeos-dev libgeos++-dev libgeos-3.8.0 libgeos-c1v5 libgeos-doc

Step 2. Install proj dependencies:

• Install cmake:

apt install cmake

• Install sqlite3:

apt install sqlite3

• Install curl devlopment package:

apt install curl && apt-get install libcurl4-openssl-dev

Step 3. Install Proj

Trying apt-get just in case it works:

Unfortunately, cartopy requires proj v8.0.0 as a minimum, but if you install proj using apt you can only install proj v6.3.1

Just for reference in case anything changes, this is the command to install proj from apt:

apt-get install proj-bin

I'm fairly sure this is all you need, but in case it's not, this command will install the remaining proj files:

apt-get install proj-bin libproj-dev proj-data

To remove the above installation, run:

apt-get remove proj-bin

or:

apt-get remove proj-bin libproj-dev proj-data

Building Proj from source

So if the above commands don't work (it's not working as of 2022/4/8), then follow the below instructions to install proj from source:

• Go to your install folder and download proj-9.0.0 (or any version with proj-x.x.x.tar.gz):

wget https://download.osgeo.org/proj/proj-9.0.0.tar.gz 

• Extract the tar.gz file:

tar -xf proj-9.0.0.tar.gz

• cd into the folder:

cd proj-9.0.0

• Make a build folder and cd into it:

mkdir build && cd build

• Run (this may take a while):

cmake ..
cmake --build .
cmake --build . --target install

• Run to make sure everything installed correctly:

ctest

The test command failed on one test for me (19 - nkg), but otherwise was fine.

You should find the required files in the ./bin directory

Finally:

• Move binaries to the /bin directory:

cp ./bin/* /bin

• As per Justino, you may also need to move the libraries:

cp ./lib/* /lib

Now after all this, you can finally install cartopy with pip:

pip install cartopy

After doing this, my cartopy still wasn't working. I went home to work on this next week, came back, and all of a sudden it was working so maybe try restarting