Unit 3 Quiz Answers

Question 1

Documentation for the command line tools is only available in the CoastWatch Utilities User’s Guide.

• True

• False

General feedback: The command line tools are documented in the appendices of the user’s guide, but also are accessible from the Unix command line as man pages. The user’s guide Chapter 1 has details on how and where to set the PATH and MANPATH variables for easy operation on Linux and Mac.

Question 2

The cwinfo tool prints out: (choose all answers that apply)

• Date and time

• Projection

• Data variables

• Modification history

General feedback: The modification history is often encoded into a data file with the attribute name history, but the cwinfo tool doesn’t show that information. For displaying full file metadata, you can try using ncdump, hdp, or HDFView (linked from the HDF and NetCDF Software page), or CDAT or hdatt (CoastWatch Utilities tools).

Question 3

The cwrender tool creates different types of images including: (choose all answers that apply)

• Color enhancements with a color bar legend

• Plots of colored vectors or wind barbs

• Three-variable RGB composites

• Contour plots of variable data

General feedback: The cwrender tool doesn’t create contour plots, but you can create plots with contour-like steps by specifying --function stepN where N is the number of steps that you want. Then ranges of values in the output image are easier to see.

Question 4

The logo in the upper-right corner of cwrender output images can’t be changed.

• True

• False

General feedback: This wasn’t mentioned in this module, but cwrender takes a --logo option to specify your own logo file, and has some built in logos discoverable using the --logolist option.

Question 5

One of the following is not a function of the cwstats tool:

• Computes the minimum, maximum, and mean of data variables

• Can limit computation to a specified fraction of the total data

• Shows the count of valid data values used in the computation

• Accepts a geographic name and radius to limit the computation

General feedback: Many of the cwstats tool features are shown on the Statistics Computations (cwstats) page, and the --region options accepts a latitude, longitude, and radius, but not a geographic name.

Question 6

The cwsample tool is a good way to get data from specific geographic locations in a data file into a comma-separated value (CSV) file for a spreadsheet program like Excel.

• True

• False

General feedback: The Sampling Locations (cwsample) page shows an example of this operation.

Question 7

One of the following is not an output format supported by the cwexport tool:

• ESRI shapefile

• Raw binary values

• GeoTIFF with 32-bit floating-point values

• NetCDF 4

General feedback: The output formats for cwexport are shown on the Data Export (cwexport) page, and ESRI shapefile format is not among them. Shapefiles aren’t generally considered a scientific data format.

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