Plotting "Bathymetry"

This task is similar to the 2003 task plotting SST. I recommended that you study that task, and adapt one of the programs found there to do this task.

bathym.dat is a subset of the Navy bathymetry files found at WORLDBATH: ETOPO5 5x5 minute Navy bathymetry. I am not going to tell you where in the world the subset is from. After you plot it, you should tell me what it is we are looking at.

I do not want you to plot the bathymetry. Rather, a plot of the topography of the land surfaces, which is included in this "bathymetry" data, is what is desired. All negative data values are below sea level, and should be plotted as one color (black, perhaps). Use a color scheme of your choice to show the structure of the topography. Convert your plot to a PNG graphic, and show it on your password protected web page. Tell me what it is. Also link the program (script) that you used to make it.

Here is the answer:

It's the north island of New Zealand! bathplot.py makes the plot, but you will need to enlarge it and flip it north-side up. Here is one way: 
convert -flip -sample 400% plot.ppm plot.png