Installing OGGM on Windows (#1666)

Co-authored-by: Anouk Vlug <anoukvlug@users.noreply.github.com>

---------

Co-authored-by: Fabien Maussion <fabien.maussion@gmail.com>
Co-authored-by: Anouk Vlug <anoukvlug@users.noreply.github.com>

docs/installing-oggm-windows.rst

@@ -0,0 +1,99 @@
+Installing OGGM on Windows
+==========================
+
+OGGM does not work on Windows. However, there is a workaround using the Windows 
+Subsystem for Linux (WSL). There is no official support for installing OGGM on 
+Windows. Nevertheless, the steps listed hereafter have been used for a successful
+installation, but there is no guarantee that it will work for everyone.
+
+Install WSL
+-----------
+Enable Intel Virtual Technology
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+As a first step, you need to enable ‘Intel Virtual Technology’ to allow WSL to be 
+executed in the next step. To do this, restart your computer and access the BIOS or 
+UEFI settings by one of the following keys: F2, F12, Esc, Del. Which key you need 
+to use depends on your computer. With the arrow key you are now able to navigate to 
+the ‘configuration’ tab. Select ‘Intel Virtual Technology’ and change the settings 
+from ‘disabled’ to ‘enabled’. Save the change and exit the BIOS or UEFI settings by 
+using F10.
+
+.. figure:: _static/windows_installation/enable_intel_virtual_technology.png
+    :width: 100%
+
+
+Enable WSL
+~~~~~~~~~~
+
+Next you need to enable WSL. This is possible through the Windows Features dialog 
+or Power Shell. In the Windows search bar, type 'features' to bring up the 
+**Turn Windows Features on or off** dialog. Scroll down and check **Windows 
+Subsystem for Linux**. It is also necessary to tick **Virtual Machine Platform** 
+and **Windows Hypervisor Platform** to avoid errors. Click ‘OK’ and in the prompted 
+new field ‘install’.
+
+.. figure:: _static/windows_installation/windows_features_on_off.png
+   :width: 40%
+|
+
+It is also possible to enable WSL as administrator via the Power Shell by using the 
+following command::
+
+    Enable-WindowsOptionalFeature -Online -FeatureName Microsoft-Windows-Subsystem-Linux
+
+Afterwards you will be asked to restart Windows.
+
+Check WSL
+~~~~~~~~~
+
+To be sure WSL is enabled you can check it by opening a Command Prompt and type ’WSL’ 
+after restarting Windows:
+
+.. figure:: _static/windows_installation/check_wsl.png
+   :width: 50%
+
+This means, WLS in enabled but you have not installed a Linux distribution yet.
+
+Download Windows Subsystem for Linux and a Linux distribution of your choice
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Download the free
+`Windows subsystem for Linux <https://apps.microsoft.com/detail/windows-subsystem-for-linux/9P9TQF7MRM4R?hl=en-us&gl=US&ocid=pdpshare>`_ 
+in the Microsoft Store. With that you keep Windows as main operating system and are able 
+work with Linux alongside your Windows application. There are some limitations compared 
+to a complete second operating system, but it is sufficient to install OGGM. In addition,
+download and install `Ubuntu <https://apps.microsoft.com/detail/ubuntu/9PDXGNCFSCZV?hl=en-gb&gl=US>`_
+or another Linux distribution of your choice. 
+
+UNIX User Account
+~~~~~~~~~~~~~~~~~
+
+Now open Ubuntu. You will automatically be asked to create a UNIX account.
+
+.. figure:: _static/windows_installation/unix_user_account.png
+   :width: 75%
+
+Installing OGGM
+---------------
+
+After successfully setting up Linux as a Windows subsystem, you can proceed with the OGGM 
+installation process. There are multiple approaches available for `installing OGGM <https://docs.oggm.org/en/stable/installing-oggm.html>`_, 
+and all of them should work with WSL. However, we are aware that this may not always be 
+the case. Here, we provide an example of steps that have resulted in a successful installation. 
+
+1. Install the `prerequisites <https://docs.oggm.org/en/stable/installing-oggm.html#prerequisites>`_ 
+for creating a python environment.
+
+2. Create a `python environment <https://docs.oggm.org/en/stable/installing-oggm.html#the-simplest-way-with-an-environment-file>`_
+using a yml file.
+
+3. `Install OGGM <https://docs.oggm.org/en/stable/installing-oggm.html#install-oggm-itself>`_
+with ``pip install oggm``
+
+4. `Test <https://docs.oggm.org/en/stable/installing-oggm.html#test-oggm>`_ if the installation was successful.
+
+5. **Congrats**, you are now set-up for the `getting started <https://docs.oggm.org/en/stable/getting-started.html>`_ section!
+
+If you encounter problems, check out the 
+`trouble shooting <https://docs.oggm.org/en/stable/installing-oggm.html#install-troubleshooting>`_ documentation.