Assignment_07

analytics.py

@@ -0,0 +1,249 @@
+'''
+Created on Feb 23, 2016
+
+@author: Max Ruiz
+'''
+
+import math
+
+'''
+Function List
+-------------
+find_largest_city(gj)
+mean_center(points)
+average_nearest_neighbor_distance(points)
+minimum_bounding_rectangle(points)
+mbr_area(mbr)
+expected_distance(area, n)
+euclidean_distance(a, b) # also in utils.py
+
+compute_critical(p)
+check_significant(lower,upper,observed)
+'''
+
+'''Assignment 5 functions'''
+
+def compute_critical(p):
+    """
+    Given a list, p, of distances (constants), determine the upper and lower
+    bound (or max and min value) of the set. The values in p are assumed floats.
+
+    Parameter(s): list p
+
+    Return(s): float lower, float upper
+    """
+    lower = min(p)
+    upper = max(p)
+    return lower, upper
+
+def check_significant(lower, upper, observed):
+    """
+    Check if given observed point is outside or within a given lower and upper
+    bound.
+
+    Parameter(s): float lower, float upper, float observed.
+
+    Return(s): boolean
+    """
+    return observed < lower or observed > upper
+
+def find_largest_city(gj):
+    """
+    Iterate through a geojson feature collection and
+    find the largest city.  Assume that the key
+    to access the maximum population is 'pop_max'.
+
+    Parameters
+    ----------
+    gj : dict
+         A GeoJSON file read in as a Python dictionary
+
+    Returns
+    -------
+    city : str
+           The largest city
+
+    population : int
+                 The population of the largest city
+    """
+
+    max_population = 0
+    for feat in gj['features']:
+        test_max_pop = feat['properties']['pop_max']
+        if test_max_pop > max_population:
+            max_population = test_max_pop
+            city = feat['properties']['name']
+
+    return city, max_population
+
+def mean_center(points):
+    """
+    Given a set of points, compute the mean center
+
+    Parameters
+    ----------
+    points : list
+         A list of points in the form (x,y)
+
+    Returns
+    -------
+    x : float
+        Mean x coordinate
+
+    y : float
+        Mean y coordinate
+    """
+    sumx = 0.0
+    sumy = 0.0
+    for coord in points:
+        sumx += coord[0]
+        sumy += coord[1]
+    x = sumx / len(points)
+    y = sumy / len(points)
+
+    return x, y
+
+
+def average_nearest_neighbor_distance_tuples(points):
+    """
+    Given a set of points, compute the average nearest neighbor.
+
+    Parameters
+    ----------
+    points : list
+             A list of points in the form (x,y)
+
+    Returns
+    -------
+    mean_d : float
+             Average nearest neighbor distance
+
+    References
+    ----------
+    Clark and Evan (1954 Distance to Nearest Neighbor as a
+     Measure of Spatial Relationships in Populations. Ecology. 35(4)
+     p. 445-453.
+    """
+    min_dist_sum = 0
+    for coord_n in points:
+        first = True
+        for  coord_m in points:
+            if coord_n == coord_m:
+                continue
+            else:
+                d = euclidean_distance(coord_n, coord_m)
+                if first:
+                    min_dist = d
+                    first = False
+                else:
+                    if d < min_dist:
+                        min_dist = d
+        min_dist_sum += min_dist
+
+    mean_d = min_dist_sum / len(points)
+
+    return mean_d
+
+def average_nearest_neighbor_distance(points, mark = None):
+    if mark != None:
+        pointsWithMark = list()
+        for x in range(len(points)):
+            if points[x].getMark() == mark:
+                pointsWithMark.append(points[x].getPoint())
+            else:
+                continue
+        return average_nearest_neighbor_distance_tuples(pointsWithMark)
+    else:
+        allPoints = list(points[x].getPoint() for x in range(len(points)))
+        return average_nearest_neighbor_distance_tuples(allPoints)
+
+def minimum_bounding_rectangle(points):
+    """
+    Given a set of points, compute the minimum bounding rectangle.
+
+    Parameters
+    ----------
+    points : list
+             A list of points in the form (x,y)
+
+    Returns
+    -------
+     : list
+       Corners of the MBR in the form [xmin, ymin, xmax, ymax]
+    """
+    xmin = 0
+    xmax = 0
+    ymin = 0
+    ymax = 0
+    for coord in points:
+        if coord[0] < xmin:
+            xmin = coord[0]
+        elif coord[0] > xmax:
+            xmax = coord[0]
+
+        if coord[1] < ymin:
+            ymin = coord[1]
+        elif coord[1] > ymax:
+            ymax = coord[1]
+
+    xcorner = xmax - xmin
+    ycorner = ymax - ymin
+    mbr = [0,0,xcorner,ycorner]
+
+    return mbr
+
+
+def mbr_area(mbr):
+    """
+    Compute the area of a minimum bounding rectangle
+    """
+    length = mbr[3] - mbr[1]
+    width = mbr[2] - mbr[0]
+    area = length * width
+
+    return area
+
+
+def expected_distance(area, n):
+    """
+    Compute the expected mean distance given
+    some study area.
+
+    This makes lots of assumptions and is not
+    necessarily how you would want to compute
+    this.  This is just an example of the full
+    analysis pipe, e.g. compute the mean distance
+    and the expected mean distance.
+
+    Parameters
+    ----------
+    area : float
+           The area of the study area
+
+    n : int
+        The number of points
+    """
+
+    expected = 0.5 * math.sqrt(area / n)
+    return expected
+
+def euclidean_distance(a, b):
+    """
+    Compute the Euclidean distance between two points
+
+    Parameters
+    ----------
+    a : tuple
+        A point in the form (x,y)
+
+    b : tuple
+        A point in the form (x,y)
+
+    Returns
+    -------
+
+    distance : float
+               The Euclidean distance between the two points
+    """
+    distance = math.sqrt((a[0] - b[0])**2 + (a[1] - b[1])**2)
+    return distance

io_geojson.py

@@ -0,0 +1,33 @@
+'''
+Created on Feb 23, 2016
+
+@author: Max Ruiz
+'''
+import json
+
+'''
+Function List
+-------------
+read_geojson(input_file)
+'''
+
+def read_geojson(input_file):
+    """
+    Read a geojson file
+
+    Parameters
+    ----------
+    input_file : str
+                 The PATH to the data to be read
+
+    Returns
+    -------
+    gj : dict
+         An in memory version of the geojson
+    """
+    # Please use the python json module (imported above)
+    # to solve this one.
+
+    with open(input_file,'r') as f:
+        gj = json.load(f)
+    return gj

point.py

@@ -0,0 +1,41 @@
+'''
+Created on Mar 15, 2016
+
+@author: Max Ruiz
+'''
+
+
+class Point(object):
+
+    def __init__(self, x, y, mark = None):
+        self.x = x
+        self.y = y
+        self.mark = mark
+
+    def __add__(self, other):
+        return Point(self.x + other.x, self.y + other.y)
+
+    def __eq__(self, other):
+        return self.x == other.x and self.y == other.y
+
+    def __neg__(self):
+        return Point(-self.x, -self.y)
+
+    def check_coincident(self, point):
+        return (self.x == point[0] and self.y == point[1])
+
+    def shift_point(self, x_shift, y_shift):
+        self.x += x_shift
+        self.y += y_shift
+
+    def getx(self):
+        return self.x
+
+    def gety(self):
+        return self.y
+
+    def getPoint(self):
+        return (self.x, self.y)
+
+    def getMark(self):
+        return self.mark