def calcMaxDensity (allPaths, limit, field): global MAXTAZ max = -1 # If there isn't a TAZ, we should just skip it gracefully. for start in LIM.getStudyArea(): paths = allPaths[start] if len(paths[start]) > 0: (num, avg, sd) = TAZ.calculateDestinationData(paths, field) if avg > max: max = avg return max
def outputDestinationsWithinLimit(allPaths, limit):
global MAXTAZ
# First, write out the file that contains all of the destinations
# under this time limit.
# This file creates a list of origin TAZs and all of the destinations
# that match criteria and can be reached within the time limit.
# Useful for exploration (creating sample maps) and understanding
# the implications of a low (or high) travel time limit.
dest = open ('destinations-within-%s.csv' % limit, 'w')
# If there isn't a TAZ, we should just skip it gracefully.
for start in LIM.getStudyArea():
paths = allPaths[start]
if len(paths[start]) > 0:
# Output the possible destinations
for k, v in paths.iteritems():
dest.write("%s, %s\n" % (start, TAZ.stripBrackets(map(lambda l: l[0], v))))
dest.close()
def generateResultsTable (dbName, limit):
global MAXTAZ
print "Precalculating all paths in the transporation zone."
counter = 0
allPaths = {}
for start in LIM.getStudyArea():
paths = TAZ.getPossibleDestinations(start, limit)
allPaths[start] = paths
print '.',
counter += 1
if counter % 10 == 0:
print
if counter % 100 == 0:
print
# Max avg. job density: 45242.506294
# Max avg. food density: 2.137048
# First, generate all the destinations within the time limit.
destinationPaths = outputDestinationsWithinLimit(allPaths, limit)
# Calculate maximums
maxAverageJobDensity = calcMaxDensity(allPaths, limit, 'emp_dens')
maxAverageFoodDensity = calcMaxDensity(allPaths, limit, 'food_store_dens')
# Calculate the ranges for the rating system.
# Why divide by six? It worked well for separating out the data.
# Also, ArcGIS does not do well with more than 5 or 6 colors in terms
# of visualizing data, so we limited our categorization to six.
jobRatingDiv = maxAverageJobDensity / 6
foodRatingDiv = maxAverageFoodDensity / 6
print
print "Max avg. job density: %s" % maxAverageJobDensity
print "Max avg. food density: %s" % maxAverageFoodDensity
print
# This file holds the CSV output of our calculations.
final = open ('final-%s.csv' % limit, 'w')
# Write a header to the CSV file.
final.write("%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s\n" % \
('SrcTAZ', 'AccessRate', \
'MedIncSrcTAZ', 'SumTotPopSrcTAZ', 'PopDensSrcTAZ', \
'NumDest', \
'JobNum', 'AvgJobDensAtDests', 'JobDensRating', 'SDJobDens', \
'FoodNum', 'AvgFoodDensAtDest', 'FoodDensRating', 'SDFoodDens' \
))
# If there isn't a TAZ, we should just skip it gracefully.
for start in LIM.getStudyArea():
paths = allPaths[start]
if len(paths[start]) > 0:
(jobNum, jobAvg, jobSD) = TAZ.calculateDestinationData(paths, 'emp_dens')
(foodNum, foodAvg, foodSD) = TAZ.calculateDestinationData(paths, 'food_store_dens')
(income, income_quart) = TAZ.getIncome(start)
(sum_totpop, pop_dens) = TAZ.getPopDens(start)
# We want a rating that is an integer value. So, we use //, which means
# "do integer division". This means that 10 // 3 = 3.
# However, because // does a "floor" operation (meaning, it rounds down)
jobRating = int(jobAvg // jobRatingDiv) + 1
foodRating = int(foodAvg // foodRatingDiv) + 1
accessRating = jobRating + foodRating
if LIM.isGoodRating(accessRating) and LIM.isIncomeLimit(income):
final.write("%i,%i,%i,%i,%.2f,%i,%i,%.2f,%i,%.2f,%i,%.2f,%i,%.2f\n" % \
(start, accessRating, \
income, sum_totpop, pop_dens, \
len(paths[start]), \
jobNum, jobAvg, jobRating, jobSD, \
foodNum, foodAvg, foodRating, foodSD))
# Cleanup nicely.
final.close()
