Also credit to Xan for the JSON parsing code; the Open Notify site delivers a JSON file that looks like this:
and is parsed with this JSL: locationData = JSON:parse( where ) after fetching the JSON above into where. Getting the values from the locationData then looks like lat[idx] = locationData["iss_position"]["latitude"]; where the lat variable (and a lon variable too) will later plot the points in the graph. A trimmed-down version of the JSON parser is in the first 70 lines of the file, followed by the code for this post.
The JSL contains a number of commands to adjust the axes and frame to make the country outlines and bitmap line up better...turning off the projection and positioning the bitmap. There is also a JSL Scheduler to update the display every 30 seconds.