"""
University of Washington, Department of Geography
Geography 465 Winter 2009

LAB ASSIGNMENT 1
Author: Michalis Avraam

Basic Data Manipulation and Analysis (Python Fundamentals)

You are given two tuples that represent a straight linear feature (line1, line2)

You are asked to perform the following:
	1. Identify the number of points in each line
	2. Identify the equation of the two lines
	3. Identify if the lines intersect
	4. Print your results in the screen

"""


# *********************************************************************************
#
# DATA PROVIDED - DO NOT ALTER
#
line1 = ((0.0, -1.0), (1.0, 1.0), (2.0, 3.0), (3.0, 5.0), (4.0, 7.0), (5.0, 9.0), (6.0, 11.0), (7.0, 13.0), (8.0, 15.0), (9.0, 17.0))
line2 = ((0.0, 2.0), (1.0, 1.0), (2.0, 0.0), (3.0, -1.0), (4.0, -2.0), (5.0, -3.0), (6.0, -3.0), (7.0, -5.0), (8.0, -6.0), (9.0, -7.0))


# *********************************************************************************
#
# IDENTIFY THE NUMBER OF POINTS IN EACH LINE
#
# Python includes multiple tools that allow us to investigate data.
#  The simplest tool we can use in this case, is to measure the
#  elements in the tuple. This is performed with the len() function.
#  It accepts one argument and returns a number. If I need the length
#  of something, I can say: length = len("String to measure")
line1Points = 0

line2Points = 0


# *********************************************************************************
#
# CODE TO IDENTIFY EQUATIONS OF LINES
#
# Straight lines have an equation of the form y = mx + b, where x, y are
#  coordinates in space, m is the slope of the line and b is the intersect.
#  You need to identify the slope (m) and intersect (b) of the lines.
#  Slope is defined as the ratio of rise over run, or the difference in
#  the y-axis over the difference in the x-axis.

# General procedure:
# 1. Grab two points from line
# 2. Find the difference in y-values
# 3. Find the difference in x-values
# 4. Divide the two to get your slope
# 5. To find the intersect, solve the equations b:
#    y = mx + b	-> b = y - mx
#	Since you have a point in the line and slope, solve to find b

slopeLine1 = 0

interLine1 = 0

slopeLine2 = 0

interLine2 = 0



# *********************************************************************************
#
# CODE TO IDENTIFY THE LINE INTERSECTION
#
# Two lines intersect when their equations have a solution in x,y that is the
#  same (meaning, there is a position they will both pass through). In order
#  to find that, we need to equate the two lines, once in the y-axis and once
#  in the x-axis. The results looks like the following:
#   line 1: y = m1x + b1
#   line 2: y = m2x + b2
#     Equating the two... (line 1 = line 2)
#     m1x + b1 = m2x + b2
#       Solving the equation for x gives us their common x-coordinate
#       x = (b2 - b1) / (m1 - m2)
#			Knowing x, plug it in one of the two equations and you get a y.
#			The x, y pair is the point of intersection

interX = 0

interY = 0


# *********************************************************************************
#
# PRINT RESULTS TO USER IN A PRETTY WAY
#
# Make sure you print the following:
# Line 1 Information :
#  Number of Points in line
#  Slope of line (m1)
#  y-intercept (b1)
# Line 2 Information:
#  Number of Points in line
#  Slope of line (m2)
#  y-intercept (b2)
# Line Intersection
#  x, y coordinates of line intersection