# View NetCDF Files Using ncview

Another useful tool for visualizing NetCDF files is ncview.  Ncview allows 
quick and easy, push-button visualizations of data within NetCDF files.
You can view your data in simple movies, along various dimensions, with different color maps, etc... 

## Installation instructions

There are two different ways you can install ncview on your computer.  The first way is to install ncview in a conda environment.  The second is to install the tool on your computer using Homebrew or from the source code directly.  For the workshop, we recommend installing ncview using conda within a conda environment.  Other installation options are also provided below. 

### Conda

Open a terminal and either activate an existing conda environment or create a new conda environment to install ncview in.  

 1) Ensure you have the correct dependencies. 

    a) Type `conda config --add channels conda-forge` and hit enter. 

    b) Type `conda config --set channel_priority strict` and hit enter. 

 2) Type `conda install ncview` and hit enter. 

### Installation on MacOS 

 1) Open the terminal, type `brew install ncview` and hit enter.

### Installation on Windows

For windows, you need to download the source code from [here](https://cirrus.ucsd.edu/ncview/).  Then you need to configure the source code, using the following steps: 

 1) Extract the archive: tar xvf ncview-*.tar.gz. 
 2) Change directory: cd ncview-*. 
 3) Configure the build: ./configure --with-udunits2_incdir=/path/to/udunits/include --with-udunits2_libdir=/path/to/udunits/lib --prefix=/path/to/install. 
 4) Compile and install: make && make install. 
 5) Add the installation path to your PATH environment variable. 

### Installation on Linux

Open the terminal. 

 1) Terminal command option
 
    b) Type `sudo apt-get install ncview` and hit enter.

 2) Homebrew option

    a) Type `brew install ncview` and hit enter.

Once ncview is installed, you can type in your terminal `ncview myFileName.nc` to load up ncview and start visualizing aspects of your NetCDF file. 

## Ncview Examples

This section includes how to navigate the ncview viewer for a 3D dataset (2D and time).  We will be using the stratocumulus_clouds.nc file from the workshop shared Google Drive folder for the following examples.  To follow along, please download the stratocumulus_clouds.nc file to your computer. 

   1) Type `ncview stratocumulus_clouds.nc` into your terminal and press enter.  

```{image} _static/ncviewer.png
:align: center
```

The ncview console along with the stracumulus_clouds.nc viewer will pop up on your screen.  The stratocumuls_clouds.nc viewer is showing cloud depth values in kilometers over an x-y grid.  On the ncview console, you can change the colormap using the button that says **3guass**.  You can left and right click to go forward and backwards respectively.  The button that says **InvC** will reverse the colormap and the button that says **Linear** will change the colormap scale. 

   2) Press the **3gauss** button until the button says **bw** and the stratocumulus_clouds.nc viewer is dark grey.

```{image} _static/ncview_bw.png
:align: center
``` 

To view cloud depth values over time, you can press the double arrow botton on the right of the pause button.  To pause the simulation, press the pause button.  To view one plane at a time, press the single arrow button to the right of the pause button.  To restart the simulation, press the button with an arrow and a 1 next to the **Quit** button.  

   3) Click on any point within the stratocumulus_clouds viewer.

```{image} _static/ncview_1_track.png
:align: center
```

By clicking somewhere in the viewer, you can visualize the cloud depth values over time at a specific coordinate point. If you want to close the panel, hit the **close** button at the top left of the panel.  If you hit the red **x** at the very corner the entire ncviewer will close and you will have to relaunch ncview.  

   4) Click on two different points within the stratocumulus_clouds viewer. 

```{image} _static/ncview_2_tracks.png
:align: center
```

You can view multiple coordinates' cloud depth values over time by clicking on multiple coordinates within the stratocumulus_clouds.nc viewer.