Unit 3 Overview

In this unit, we'll learn how to use the command line tools in the CoastWatch Utilities for:

  • Showing file content information (cwinfo)
  • Rendering data to an image (cwrender)
  • Computing data statistics (cwstats)
  • Extracting samples of data at specific locations (cwsample)
  • Exporting to other data formats (cwexport)

Prerequisites

To follow along and perform your own command line calls, the CoastWatch Utilities command line tools must be installed.  If your operating system is Windows or Mac, there was an option in the CoastWatch Utilities installation wizard for the command line tools. For Linux users, the command line tools are always included in the tar.gz distribution file.  For all operating systems, the command line tools reside in the bin/ directory of the installation path.  In the content overview page we mentioned that the command line tools are most easily used when the PATH variable is set in your terminal program:

  • On Windows this is called the Command Prompt or Windows PowerShell
  • On Linux it's either xterm or Terminal
  • On Mac it's called Terminal and is found inside the Utilities folder of the system Applications

Linux and Mac users will also benefit from setting the MANPATH so that the Unix man program will find the command line tool manual pages.  See the CoastWatch Utilities User's Guide Download CoastWatch Utilities User's Guide Chapter 1 for details on how and where to set the PATH and MANPATH variables.  The user's guide also has all the manual pages for the command line tools in Appendix A as an alternative to using the Unix man pages.

Resources

For the exercises in this unit, you'll need to download the cw_utils_sample_data.zip Download cw_utils_sample_data.zipfile that contains all the sample data for the course.  Inside the ZIP file is a table of contents 00-Contents.txt that describes all the data files — we'll use a subset of the data files in this unit.

Supplementary reading material is available in the user's guide (see link above) in the following sections:

  • Chapter 2 - Common Tasks
  • Appendix A.1 - Information and Statistics
  • Appendix A.2 - Data Processing
  • Appendix A.3 - Graphics and Visualization

If you prefer to learn by watching videos, there are two YouTube videos with a narrated demonstration of command line tool and CDAT features: