Homework: Map Drawing
Homework: Map Drawing
Your job is to use turtle graphics and file input to draw a roadmap from a description given to you in a map data file.
The input file format is a series of lines of text. Each line consists of fields separated by commas.
The first field is an item type field. The item type is a single character. The possible item types are:
c': The item is a city. The next fields are the x-coordinate, the y-coordinate, the name and the population. The x and y coordinates are numbers in the range -200 to 200. The name is a string of letters, digits spaces and underscores. Every city item will have a unique name. The population is an non-negative integer.
If the city has a population of zero, it is just a point on the map: it need not be drawn. If it has a population in the range 1 to 90000 it is a town, and should be drawn as a small open circle with its name to its right. If it has more than 90000 it is a large city, and should be drawn as a larger filled circle with its name to its right.
r': The item is a road. The next fields are the names of the two endpoints of that road, which will have previously been given by '
c' commands. The road should be drawn as a solid line.
You may read the map data file from stdin, or from a file whose name is given on the command line&emdash;whichever is easier for you.
You can download a couple of sample map data files. The first is
a very simple demo map. The output of my program when given
this map as input is
The second sample map data file is
I'll let you render that one for yourself.
At the very least you'll need to import the Python 3
graphics library module. Its documentation is
This assignment will use much more of the library than we
have in class, so study its documentation a bit. In
particular you'll need the
functions as well as the
functions to complete the assignment. Depending on your
platform, you may want to finish the program with a call
turtle.done() to get it to wait for you to look at
You'll probably also want to import the Python 3
library module for reading files of comma-separated values. Its
You could instead "roll your own", but this module is pretty
easy to use and will take care of most of the heavy lifting
for you. Don't forget to convert strings to numbers when you
need to, though!
You'll need to import the
sys module if you want
stdin. If you decide to go with reading arguments and
then opening a file, you can either read the filename
directly out of
sys.argv or use something heavyweight like
argparse module. (I don't recommend the
getopt modules, as the former is deprecated and the latter
has a terrible programmer interface.)
You'll probably want a dictionary of cities keyed by name,
which means that you'll want a
City class to describe city