Unit 5 Quiz Answers

Question 1

The cwmath tool: (choose all answers that apply)

• Computes a value at each pixel in the input data file

• Handles multiple input data files

• Can save data to a 10-bit integer data type

• Uses a C/C++/Java expression syntax

General feedback: The features of the cwmath tool are shown on the Generic Variable Math (cwmath) page. You’ll find in the manual page that the --size option allows for 8-bit, 16-bit, 32-bit, and 64-bit output data, but not 10-bit. You could fit 10-bit data (0-1023) into the least significant bits of a 16-bit value.

Question 2

The cwregister2 tool can use multiple CPU threads in parallel.

• True

• False

General feedback: The cwregister2 tool runs by default in parallel mode. You can change this behaviour using the --serial or --threads options.

Question 3

The cwmaster tool can read and write map projection master templates for:

• Polar Stereographic

• Albers Equal Area

• Mercator

• Icosahedral

General feedback: You can run the cwmaster tool to discover all the supported map projections. They’re also listed in Section B.6 - GCTP Appendices in the user’s guide. Icosahedral is not one of them, but it is a map projection — NOAA has a printable demonstration of an icosahedral projection available.

Question 4

The cwcomposite tool accepts multiple input data files and computes at each pixel location:

• The mean, median, minimum, maximum, or latest data value

• The difference between the largest and smallest data values

• The standard deviation of the data values

• The bitwise AND of all data values

General feedback: The full list of possibilities for computing a composite data value are listed on the cwcomposite tool manual page under the --method option. By default the mean value is computed.

Question 5

Using a BeanShell script, the cwscript / cwgscript tools don’t have access to the GUI part of the CoastWatch software library API.

• True

• False

General feedback: All of the CoastWatch software library API is accessible from a BeanShell script. An example of a GUI script is shown on the Direct Software Library Access (cwscript) page.
### Question 6

Calls to the CoastWatch Utilities command line tools can be automated by running them from:

• Unix shell scripts

• Windows batch files

• Python code

• Any of these programming languages

General feedback: Any programming language that can call a function to run a program can be used to run the CoastWatch command line tools. For example, other options include Perl and C.

---

« Previous