''' Purpose: determine a rough estimate of the geocenter of the
        continental USA
'''

# get access to web-based data support
import url

# specify dataset web location
CSV_WEB_FOLDER = 'http://www.cs.virginia.edu/~cs1112/datasets/csv/'

USA_DATASET    = CSV_WEB_FOLDER + 'continental-usa.csv'


# get the dataset of interest
dataset = url.get_dataset( USA_DATASET )


# determine webfile header and location data
header    = dataset[0]
locations = dataset[1:]


# determine geocenter

#determine number of locations
nbr_locations = len(locations)

#determine the column number of zipcodes, latitudes, and longitudes
zip_index  = header.index( 'Zipcode' )
lat_index  = header.index( 'Latitude' )
long_index = header.index( 'Longitude' )

#print( zip_index, lat_index, long_index )

# accumulate a list of all zipcodes, then latitudes, and then longitudes
zips  = []
lats  = []
longs = []

for row in locations:
    zipcode   = row[ zip_index ]
    latitude  = row[ lat_index ]
    longitude = row[ long_index ]

    zips.append( zipcode )
    lats.append( latitude )
    longs.append( longitude )

#print ( 'zips:', zips[0:10] )
#print ( 'lats:', lats[0:10] )
#print( 'longs:', longs[0:10] )

# sort lists from smallest to largest
zips  = sorted( zips )
lats  = sorted( lats )
longs = sorted( longs )

#print ( 'sorted zips:', zips[0:10] )
#print ( 'sorted lats:', lats[0:10] )
#print( 'sorted longs:', longs[0:10] )

# get min and max entries of the zips, lats, and longs
min_zip  = min(zips)
min_lat  = min(lats)
min_long = min(longs)

max_zip  = max(zips)
max_lat  = max(lats)
max_long = max(longs)

# get median row
median_index = nbr_locations // 2

median_zip  = zips[ median_index ]
median_lat  = lats[ median_index ]
median_long = longs[ median_index ]


ave_min_max_zip  = ( min_zip + max_zip )   // 2
ave_min_max_lat  = ( min_lat + max_lat )   / 2.0
ave_min_max_long = ( min_long + max_long ) / 2.0

print( median_lat, median_long )
print( ave_min_max_zip )
print ( ave_min_max_lat, ave_min_max_long )


#get the sum of the lists after class


#get average zipcode, latitude, longitude