Question: Homework 3 – Data extraction, conversion, filter, …SOLVED

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Question: Homework 3 – Data extraction, conversion, filter, …SOLVED

Homework 3 – Data extraction, conversion, filter,
sort, and build a CSV file output

Abstract
As discussed in Homework 1 many ETL (extraction, transformation, and loading) problems parse data files wherein the data fields is separated by commas. This
assignment is a continuation of that process – with an additional two steps. The first
step is to convert the input file’s latitude and longitude from sexagesimal (base 60)
degrees to decimal degrees. For example, the inputs are in the form: degrees,
minutes and seconds, arcseconds and direction. The outputs are in the form: sign,
degrees, and decimal fractions to represent the same value.
Therefore this assignment requires the data extraction, degree conversion, data
formatting, sorting, and output. The file inputs are defined in the Inputs, as are the
outputs.
This assignment has an additional two requirements. The first is to sort the airports alphabetically. The second is to sort the airports geographically and plan a
route from south to north, all the while flying over land
1 Objectives
The objectives of this assignment are to demonstrate proficiency in file I/O, data structures, data transformation, sorting techniques, and file output using C language resources.
1.1 Inputs
There are two basic inputs, the input file name, and the input file data sort order defined
below. The input file data is defined below.
1
1.1.1 Command Line arguments
• The input file name and sort parameters are input from the command line as
shown below.
hw3Sort filename.ext sortParameter
• In the event that the filename.ext is not available, an appropriate error message
shall be displayed. Use the example below for guidance.
hw3Sort ERROR: File “bogusFilename” not found.
• It would be appropriate to display the valid sort parameters in the error message.
The valid sort parameters are a for alphabetical sort or n for North Bound Exit.
The sort parameters can be entered in either upper or lower case.
hw3Sort ERROR: valid sort parameters are a or n.
1.2 Input File fields
The CSV input file contains the following fields. Please note these fields may vary
in size, content, and validity of the data. Also note that some of the data formats
are a melange of types. Specifically, note that both latitude and longitude contain
numbers, punctuation, and text. Likewise, the FAA Site number contains digits, letters,
and punctuation. (This assignment will treat all input data as character data. Data
conversion for some data is specified in greater detail below.)
1.3 Processing the data structure
The data conversions for this assignment, specified below, require a certain degree of
parsing and calculation. Initially reading the input is to your advantage to deal with
all data elements as character data. And then process the latitude and longitude, hereinafter referred to as degrees. The degrees are expressed as sexagesimal (base 60)
numbers. Therefore it is required to create functions to establish valid latitudes and
longitudes.
Please note that there are some airports whose Loc ID begin with numerical digits.
There are also quite a few that contain two trailing digits. Typically these are helipads.
For the purposes of this assignment those airports can be ignored or discarded from the
input. Careful review of these airports will reveal they typically start with the string FL
or X and are followed by 2 digits.
Therefore, it is highly recommended to discard any airport that does not contain three
or four letters only.

1.3.1 Latitude/Longitude Input
The latitude and longitude are both degrees, expressed as shown in the tables below.

The conversion of the DDD-MM-SS.MASD string is shown in Table 2. The formula to convert a sexagesimal degree measurement to a digital degree measurement is
shown below.
degrees
decimal
= ±DDD + MM/60 + SS.MAS/60
2
Note that the ± is derived from the information in Table 3 above.
1.4 Functions
1.4.1 float sexag2decimal(char *degreeString);
Description: Convert the sexagesimal input string of chars to a decimal degree based
on the formula in Tables 2 and 3.
Special Cases: If a NULL pointer is passed to this function, simply return 0.0. Similarly, if the DD-MM-SS.MASD fields have invalid or out-of-range data, return
0.0.
Caveat: Even though the valid range of Degrees is from 0 to 180, the data files for the
Continental US and Florida are from 0 to 99. Make sure that the conversion can
handle all valid cases correctly.

Hint: Take care to make sure the values for each numeric component are within their
valid ranges. Refer to Table 2 for the ranges.
Returns: A floating point representation of the calculated decimal degrees or 0.0 in
the special cases mentioned above.
1.4.2 void sortByLocID(lListAirPdata *airports);
Description: Sorts the airports alphabetically by the string named Loc ID. Remember
that the Loc ID has been filtered to three or four letters.
Special Cases: Remember the helipads! In other words, it is recommended to skip
airports whose Loc ID begin with a number, or start with either FL or X followed
by two digits. Therefore, it is recommended to discard any airport whose LocID
is not three or four letters.
Caveat: Since the sorting options are mutually exclusive, this function can destructively manipulate the input list to produce the desired results.
Returns: Nothing. However the input data should be seriously modified by this process.
1.4.3 void sortByLatitude(lListAirPdata *airports);
Description: Sorts the airports by latitude from South to North. Think of this as an
Escape from Key West to Georgia.
Special Cases: Remember the helipads! In other words, it is acceptable to skip airports whose Loc ID begin with a number, or start with either FL or X followed
by two digits. Remember, it is recommended to discard any Loc ID that does not
contain three or four letters only.
Output: Output the airports’ data per the output file specification derived from walking thru the AVL tree until reaching the maximum latitude for the Florida border.
For the purposed of this exercise, assume 31 degrees North.
Caveat: Since the sorting options are mutually exclusive, this function can destructively manipulate the input list to produce the desired results.
Hint: Remember to use the the converted Latitude as a measurement criteria for building an AVL tree.
Returns: Nothing. However the input data could be seriously modified by this process.

2 Outputs
The outputs of the program will be populated Struct airPdata data. This data
will be formatted so as to provide output as defined in the following sections.
2.1 Data Structure
The structure struct airPdata is described below. Please note the correlation
with the data file’s Field Names refer to Table 1 on page 3 for more information. NB
The Javascript APIs and many other APIs for plotting geographic data REQUIRES
that longitude is before latitude.

typedef struct airPdata{
char* LocID; //Airport’s ‘‘Short Name’’, ie MCO
char* fieldName; //Airport Name
char* city; //Associated City
float longitude; //Longitude
float latitude; //Latitude
} airPdata;

2.2 File output
The file output for this assignment is stdout, aka the console. Make sure there is a
headline that names each column. For example:
code,name,city,lat,lon
DAB,DAYTONA BEACH INTL,DAYTONA BEACH,29.1797,-81.0581
FLL,FORT LAUDERDALE/HOLLYWOOD INTL,FORT LAUDERDALE,26.0717,-80.1494
GNV,GAINESVILLE RGNL,GAINESVILLE,29.6900,-82.2717
JAX,JACKSONVILLE INTL,JACKSONVILLE,30.4939,-81.6878
EYW,KEY WEST INTL,KEY WEST,24.5561,-81.7594
LAL,LAKELAND LINDER RGNL,LAKELAND,27.9889,-82.0183
MLB,MELBOURNE INTL,MELBOURNE,28.1025,-80.6450
MIA,MIAMI INTL,MIAMI,25.7953,-80.2900
APF,NAPLES MUNI,NAPLES,26.1522,-81.7756
SGJ,NORTHEAST FLORIDA RGNL,ST AUGUSTINE,29.9592,-81.3397
ECP,NORTHWEST FLORIDA BEACHES INTL,PANAMA CITY,30.3581,-85.7956
OCF,OCALA INTL-JIM TAYLOR FIELD,OCALA,29.1717,-82.2239
MCO,ORLANDO INTL,ORLANDO,28.4292,-81.3089
Things to note:
• Digital degrees are expressed as floating point numbers of varying digits of precision. This is an artifact of Javascript usage by many APIs. In this exercise 4
digits to the right of the decimal point is sufficient.
• The first line of the file identifies the field names. This is a material fact and
will adversely impact the output of the data in the webpage. Capitalization and
spelling matter – and must match the first line above.
• The text shown above has been converted to uppercase as a piece of information
to help debugging. String case conversion is not required for this exercise.

3 Processing
The primary goal is to provide programmatic access to the data from the input CSV
file. This must be accomplished using standard C file IO techniques. Also note that
it is vital to utilize the stuct airPdata for all data retrieval/extraction and conversion.
Likewise, use of the stuct airPdata is required for the file output.
3.1 Reading the input
There are several approaches to read the input. Perhaps the most important consideration is reading the line in for each airport. Please note that there is one line per airport.
Also note, that once the line is read into the input buffer it might be advantageous to
parse the input buffer based on the comma delimiter.
There are several approaches possible. Make sure to test on Eustis as line termination characters/behaviors vary amongst operating systems.
Make sure that the output is formatted with decimal degrees.
3.2 Testing
The input files used in Homework 1 will be used as an additional testing file. Errors
may be induced for the degrees.
There will be two files provided for program testing. They are described below.


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