# Project dependencies

## Description

This project requires these following dependencies.

### NetCDF4

- [NetCDF](https://www.unidata.ucar.edu/software/netcdf/) is C library to read and edit NetCDF files;
- [NetCDF4](https://github.com/Unidata/netcdf4-python) is a Python wrapper for NetCDF, which requires the NetCDF
library, used here to read NetCDF files.

-> Documentation is available [here](http://unidata.github.io/netcdf4-python/).

### pycdf

- [SpacePy](http://pythonhosted.org/SpacePy/index.html) is a python package for space sciences;
- [pycdf](http://pythonhosted.org/SpacePy/pycdf.htm) is a SpacePy sub-package used to read and write CDF files.

-> Documentation is available [here](http://pythonhosted.org/SpacePy/pycdf.htm).

### Sphinx

Sphinx is a documentation generator for Python projects.

-> Documentation is available [here](http://www.sphinx-doc.org/en/stable/).

## Installing environment and dependencies

Here we will install dependencies in Python environments.

### Case 1: If you have NetCDF installed on your machine

You can use pip and virtualenv:

```bash
pip install virtualenv  # installing virtualenv
virtualenv -p python3 nc2cdf  # creating virtualenv
source nc2cdf/bin/activate  # (or ". nc2cdf/bin/activate.fish" on Fish shells) activating virtualenv
pip install -r install/pip_req_nc2cdf.txt  # installing dependencies
```

Then, each time you need to run one of the script in this project, activate the environment first:

```bash
source nc2cdf/bin/activate
```

And you can deactivate it with:

```bash
deactivate
```

### Case 2: If you don't have NetCDF installed on your machine

The easier way is to use [Anaconda](https://docs.continuum.io/), which is a tool to install compiled Python dependencies
 in environments.

First, [install Anaconda3](https://docs.continuum.io/anaconda/install).

The installer may propose you to add Anaconda to your system path, but this will set the Anaconda Python interpreter as
the default Python interpreter,
which might be a problem. I recommend to add an alias which both add Anaconda to your path and source the environment.
Edit your system startup file (usually `.bashrc`):

```bash
alias conda3="export PATH=$HOME/.anaconda3/bin:$PATH && source activate"
```

or on Fish shell:

```bash
alias conda3="set PATH $HOME/.anaconda3/bin/ $PATH; and source $HOME/.anaconda3/etc/fish/conf.d/conda.fish; and activate"
```

> **Note:** this procedure will also allow you to manage several Anaconda versions (ie. 2 and 3) by using several
> aliases.

Now, create the environment (required only for the first time), supposing the Anaconda installation path is
`$HOME/.anaconda3/`:

```bash
export PATH=$HOME/.anaconda3/bin:$PATH  # or "set PATH $HOME/.anaconda3/bin/ $PATH" on Fish shells
conda create -f install/conda_env_nc2cdf.yml
```

Then, each time you need to run one of the script in this project, activate the environment first:

```bash
conda3 nc2cdf
```

And you can deactivate it with:

```bash
deactivate
```

### That's all!

You can now run all scripts in this project:

```
./create_granules.py
```

## Build the documentation

To be completed