AddressToLatLon.m

%%

%% AddressToLatLon

%%

%% Given a street address, returns (latitude, longitude).

%%

%% Example:

%% [lat, lon] = AddressToLatLon('851 S. Morgan St, Chicago IL');

%%

%%

%% References:

%% https://www.mathworks.com/matlabcentral/fileexchange/24126-google-geocode-api

%% https://www.mathworks.com/matlabcentral/fileexchange/20565-json-parser

%%

%%

function [lat,lon] = AddressToLatLon(address)

retries = 3;

while retries > 0

try

%% try to get (latitude, longitude) from google:

address = strrep(address, ' ', '%20');

google = ['https://maps.googleapis.com/maps/api/geocode/json?address=',address];

result = parse_json(urlread(google));

lat = result{1}.results{1}.geometry.location.lat;

lon = result{1}.results{1}.geometry.location.lng;

break; %% success, break out of the loop

catch ME

%% it failed, let's try again (at most 3 times):

retries = retries - 1;

lat = 0;

lon = 0;

pause(1.0); %% wait 1 second before trying again:

end

end

end

function [data json] = parse_json(json)

% [DATA JSON] = PARSE_JSON(json)

% This function parses a JSON string and returns a cell array with the

% parsed data. JSON objects are converted to structures and JSON arrays are

% converted to cell arrays.

%

% Example:

% google_search = 'http://ajax.googleapis.com/ajax/services/search/web?v=1.0&q=matlab';

% matlab_results = parse_json(urlread(google_search));

% disp(matlab_results{1}.responseData.results{1}.titleNoFormatting)

% disp(matlab_results{1}.responseData.results{1}.visibleUrl)

data = cell(0,1);

while ~isempty(json)

[value json] = parse_value(json);

data{end+1} = value; %#ok

end

end

function [value json] = parse_value(json)

value = [];

if ~isempty(json)

id = json(1);

json(1) = [];

json = strtrim(json);

switch lower(id)

case '"'

[value json] = parse_string(json);

case '{'

[value json] = parse_object(json);

case '['

[value json] = parse_array(json);

case 't'

value = true;

if (length(json) >= 3)

json(1:3) = [];

else

ME = MException('json:parse_value',['Invalid TRUE identifier: ' id json]);

ME.throw;

end

case 'f'

value = false;

if (length(json) >= 4)

json(1:4) = [];

else

ME = MException('json:parse_value',['Invalid FALSE identifier: ' id json]);

ME.throw;

end

case 'n'

value = [];

if (length(json) >= 3)

json(1:3) = [];

else

ME = MException('json:parse_value',['Invalid NULL identifier: ' id json]);

ME.throw;

end

otherwise

[value json] = parse_number([id json]); % Need to put the id back on the string

end

end

end

function [data json] = parse_array(json)

data = cell(0,1);

while ~isempty(json)

if strcmp(json(1),']') % Check if the array is closed

json(1) = [];

return

end

[value json] = parse_value(json);

if isempty(value)

ME = MException('json:parse_array',['Parsed an empty value: ' json]);

ME.throw;

end

data{end+1} = value; %#ok

while ~isempty(json) && ~isempty(regexp(json(1),'[\s,]','once'))

json(1) = [];

end

end

end

function [data json] = parse_object(json)

data = [];

while ~isempty(json)

id = json(1);

json(1) = [];

switch id

case '"' % Start a name/value pair

[name value remaining_json] = parse_name_value(json);

if isempty(name)

ME = MException('json:parse_object',['Can not have an empty name: ' json]);

ME.throw;

end

data.(name) = value;

json = remaining_json;

case '}' % End of object, so exit the function

return

otherwise % Ignore other characters

end

end

end

function [name value json] = parse_name_value(json)

name = [];

value = [];

if ~isempty(json)

[name json] = parse_string(json);

% Skip spaces and the : separator

while ~isempty(json) && ~isempty(regexp(json(1),'[\s:]','once'))

json(1) = [];

end

[value json] = parse_value(json);

end

end

function [string json] = parse_string(json)

string = [];

while ~isempty(json)

letter = json(1);

json(1) = [];

switch lower(letter)

case '\' % Deal with escaped characters

if ~isempty(json)

code = json(1);

json(1) = [];

switch lower(code)

case '"'

new_char = '"';

case '\'

new_char = '\';

case '/'

new_char = '/';

case {'b' 'f' 'n' 'r' 't'}

new_char = sprintf('\%c',code);

case 'u'

if length(json) >= 4

new_char = sprintf('\\u%s',json(1:4));

json(1:4) = [];

end

otherwise

new_char = [];

end

end

case '"' % Done with the string

return

otherwise

new_char = letter;

end

% Append the new character

%%string = [string char(new_char)]; %#ok

string = strcat(string, char(new_char));

end

end

function [num json] = parse_number(json)

num = [];

if ~isempty(json)

% Validate the floating point number using a regular expression

[s e] = regexp(json,'^[\w]?[-+]?[0-9]*\.?[0-9]+([eE][-+]?[0-9]+)?[\w]?','once');

if ~isempty(s)

num_str = json(s:e);

json(s:e) = [];

num = str2double(strtrim(num_str));

end

end

end

DistBetween2Points.m

%%

%% Returns the distance in miles between 2 points

%% (lat1, lon1) and (lat2, lon2). One set must

%% be a point, however the other can be a single

%% point OR a vector --- in which case a vector

%% of distances is returned.

%%

%%

function Distance = DistBetween2Points(lat1, lon1, lat2, lon2)

%%

%% Reference: http://www8.nau.edu/cvm/latlon_formula.html

%%

earth_rad = 3963.1; %% statue miles:

lat1_rad = lat1 .* pi ./ 180.0;

lon1_rad = lon1 .* pi ./ 180.0;

lat2_rad = lat2 .* pi ./ 180.0;

lon2_rad = lon2 .* pi ./ 180.0;

%% distance between points in statue miles:

Distance = earth_rad .* acos(...

(cos(lat1_rad).*cos(lon1_rad).*cos(lat2_rad).*cos(lon2_rad)) ...

+ ...

(cos(lat1_rad).*sin(lon1_rad).*cos(lat2_rad).*sin(lon2_rad)) ...

+ ...

(sin(lat1_rad).*sin(lat2_rad)) ...

);

end

DivvyAnalysis.m

function Result = DivvyAnalysis(filename, analysis, optional)

%%

%% let's make sure the file exists:

%%

if exist(filename, 'file') ~= 2

fprintf('**Error: file "%s" cannot be found ', filename);

Result = '**Error: file not found';

return;

end

%%

%% Load the data:

%%

data = load(filename);

%%

%% Perform requested analysis:

%%

if analysis == 1

Result = NumRides(data);

elseif analysis == 2

Result = AverageRide(data);

elseif analysis == 3

Result = RiderPercentage(data, optional);

elseif analysis == 4

Result = AverageAge(data, optional);

elseif analysis == 5

Result = RideHistogram(data, optional);

elseif analysis == 6

Result = StationCheckouts(data, optional);

elseif analysis == 7

Result = StationCheckins(data, optional);

elseif analysis == 8

Result = Top10Checkouts(data);

elseif analysis == 9

Result = Top10Checkins(data);

else

Result = '**Error: invalid analysis parameter';

end

end

%% total # of rides in this dataset:

function Rides = NumRides(data)

[Rides, ~] = size(data);

end

%% average ride duration, in seconds:

function AvgRide = AverageRide(data)

AvgRide = mean(data(:, 5)); %% trip duration in column 5:

AvgRide = AvgRide / 60.0; %% convert to mins:

end

%% percentage of male (1) or female (2) riders:

function Percentage = RiderPercentage(data, gender)

LI = (data(:, 7) == gender);

Riders = NumRides(data);

Percentage = (sum(LI) / Riders) * 100.0;

end

%% average age of male (1) or female (2) riders:

function AvgAge = AverageAge(data, gender)

LI = ((data(:, 6) > 0) & (data(:, 7) == gender));

birthyears = data(LI, 6); %% extract matching gender with birthyears > 0

%% compute age of rider:

c = clock();

currentyear = c(1); %% year is first entry:

Ages = currentyear - birthyears;

AvgAge = mean(Ages);

end

%% # of rides each hour from midnight to 11pm; pass 0 as "gender" to

%% count all rides, otherwise 1 => male and 2 => female:

function Result = RideHistogram(data, gender)

startingHours = data(:, 4); %% column 4 contains starting hour:

if gender == 0 %% count ALL rides:

Result = histc(startingHours, 0:23); %% 24 bins, 0:23

else

LI = (data(:, 7) == gender); %% search for matching gender:

startingHours = startingHours(LI); %% extract matching rows:

Result = histc(startingHours, 0:23); %% 24 bins, 0:23

end

Result = Result'; %% we want a row vector:

end

%% total # of rides where the ride started at this station:

function Checkouts = StationCheckouts(data, stationID)

LI = (data(:, 1) == stationID); %% column 1 contains starting station:

Checkouts = sum(LI);

end

%% total # of rides where the ride ended at this station:

function Checkins = StationCheckins(data, stationID)

LI = (data(:, 2) == stationID); %% column 2 contains ending station:

Checkins = sum(LI);

end

%% which stations have the largest # of rides that originated here? Return

%% a 10x2 matrix where column 1 are the top-10 station ids and column 2 are

%% the corresponding # of rides starting from these stations:

function Result = Top10Checkouts(data)

ids = data(:, 1); %% column 1 contains starting station IDs:

ids = unique(ids); %% eliminate duplicates:

%%

%% loop can be replaced with histc(data(:, 1), ids);

%%

counts = zeros(length(ids), 1); %% column of 0's

for i = 1:length(ids)

LI = (data(:, 1) == ids(i));

counts(i) = sum(LI);

end

[counts, newOrdr] = sort(counts, 'descend');

ids = ids(newOrdr); %% reorder ids to match:

Result = [ids(1:10), counts(1:10)]; %% top-10 of each:

end

%% which stations have the largest # of rides that ended here? Return

%% a 10x2 matrix where column 1 are the top-10 station ids and column 2 are

%% the corresponding # of rides ending at these stations:

function Result = Top10Checkins(data)

ids = data(:, 2); %% column 2 contains ending station IDs:

ids = unique(ids); %% eliminate duplicates:

%%

%% loop can be replaced with histc(data(:, 1), ids);

%%

counts = zeros(length(ids), 1); %% column of 0's

for i = 1:length(ids)

LI = (data(:, 2) == ids(i));

counts(i) = sum(LI);

end

[counts, newOrdr] = sort(counts, 'descend');

ids = ids(newOrdr); %% reorder ids to match:

Result = [ids(1:10), counts(1:10)]; %% top-10 of each:

end

%%

%% GetStationName

%%

%% Given a Divvy station id, loads the Divvy file 'divvy-stations.csv'

%% and returns the station name associated with this id. Returns

%% the string 'Station not found...' if the given station id is not

%% found.

%%

%% NOTE: you must pass a single id, you cannot pass a vector of ids.

%%

%%

%% Prof. Joe Hummel

%% U. of Illinois, Chicago

%% CS109, Spring 2018

%% Project #13

%%

%%

function Name = GetStationName(id)

filename = 'divvy-stations.csv';

if exist(filename, 'file') ~= 2 %% doesn't exist:

fprintf('**Error in GetStationName: cannot find "divvy-names.csv" file ');

Name = '?';

return;

end

%% load file of station names, and search for matching id:

%% this works in MATLAB or Octave

[IDs, Names] = textread(filename, '%d %s', 'delimiter', ',');

LI = (IDs == id);

if sum(LI) == 1 %% found it!

I = find(IDs == id); %% find index of station id

Name = Names{I}; %% use { } to extract from CELL ARRAY

else

Name = 'Station not found...';

end

end

Assignment In the previous project #12 you wrote functions to analyze a file of Divvy data. This assignment is going to build on those functions to (a) visualize the data, and (b) find stations nearby. Submissions will be collected via Blackboard. Before you start, decide if you are going to use your solution to Project #12, or our provided solution. Either way, make a copy of your DivvyAnalysis.m file and rename it so your solution is not lost if/ when you copy our provided solution. Provided files: .m and.csv files A number of files are being provided to aid in the completion of this assignment; both.m and.csv files. These can be found in the on the course web page: open "Projects", then "project-13". Here are the files: AddressToLatLon.m: function to convert street address to (latitude, longitude) using Google API DistBetween2Points.m: function to compute miles between (lat1, long1) and (lat2, long2) divvvi csv. same input file as proiect #12 Assignment In the previous project #12 you wrote functions to analyze a file of Divvy data. This assignment is going to build on those functions to (a) visualize the data, and (b) find stations nearby. Submissions will be collected via Blackboard. Before you start, decide if you are going to use your solution to Project #12, or our provided solution. Either way, make a copy of your DivvyAnalysis.m file and rename it so your solution is not lost if/ when you copy our provided solution. Provided files: .m and.csv files A number of files are being provided to aid in the completion of this assignment; both.m and.csv files. These can be found in the on the course web page: open "Projects", then "project-13". Here are the files: AddressToLatLon.m: function to convert street address to (latitude, longitude) using Google API DistBetween2Points.m: function to compute miles between (lat1, long1) and (lat2, long2) divvvi csv. same input file as proiect #12