Geolocation Look-up Tables

Description

This program creates a geolocation file for GOES-16 L1b and L2 datasets. The native netCDF files contain fixed grid radian scan angle coordinates and this program calculates the corresponding latitude longitude projection fo each pixel. The result is then re-saved in a more easily viewed NetCDF file.

Converting files occurs in three simple steps:

1. Download and place files that you wish to display in the input folder.
2. Run the python script to convert files.
3. Check the output file for the results.

Getting Started

Prerequisites

This is a python script, so you will need python on your computer to run this code. If you don't know where to start, I suggest installing Anaconda Python.

Install Libraries

There are several required python libraries. The easiest way to install the libraries is to open the terminal on your respective OS:

• Windows: search for the "Anaconda Prompt" on your local computer or find it manually in your list of programs.

• Mac: open the terminal.

Then type the code below:

pip install -r requirements.txt

Running

Step 1: Update the path of the file that you want to convert in the "filename" variable

Before doing anything, you need to have ABI L2 NetCDF files. At the bottom the program, under main(), you can update the filename variable. Change the outname variable to something meaningful (should indicate if it's L1 or L2, CONUS or FD, the satellite, date generated, etc). It may take a few minutes to run, particularly with high-resolution fulldisk products.

Note: On Mac/Linux, the paths are written with a forward slash (/) whereas on PCs, it's written with two backslashes (\\)

Step 2: Run the script

Option 1: Command line

Open the terminal on your respective OS:

• Windows: search for the "Anaconda Prompt" on your local computer or find it manually in your list of programs. You will need to write the full path of the python script (including to the input files). You may have to manually tell Windows to associate python with *.py files.

• Mac: open the terminal.

You can run the script via the Anaconda Prompt or terminal by typing:

python main.py

Option 2: Run in the Spyder development environment

Open the Anaconda Navigator, run Spyder, and then open the main.py script. You can simply press the big "Play" button at the top to run the script.

Step 3: Check the Output

Finished files will be saved in as latlon-[L1b/L2]_[conus/fulldisk].nc

To check the results, NetCDF files can be easily viewed using Panoply.

Author

• Rebekah Bradley Esmaili bekah@umd.edu

More Information

• GOES-16 input data can be downloaded from NOAA's Comprehensive Large Array-data Stewardship System (CLASS).
• A detailed description of the coordinate system and the conversion to a map project can be found in Section 4.2 of the Product Definition and Users Guide, Vol. 5.
• At the time of writing, some of GOES-16 L2 products are in the Beta Phase. Data are preliminary and cannot be used for scientific research or operational use.
• Additional information on GOES-16 products can be found in the Algorithm Theoretical Basis Documents (ATBD).