Cfrgtkky

I am working with a pandas data frame where I have 4 columns of lats and langs. You can call these as pickup and drop off points. I have identify lat and lang of a central location and figured the radius (1000FT)of the circle. I want to select all the pickup and drop off points within this circle. Potentially create a column in the data frame with a flag.

(Pdb) x.dtypes

Pickup_longitude     float64

Pickup_latitude      float64

Dropoff_longitude    float64

Dropoff_latitude     float64

dtype: object



Pickup_longitude,Pickup_latitude,Dropoff_longitude,Dropoff_latitude

-73.97948455810547,40.68495559692383,-73.97943115234375,40.685020446777344

-74.01079559326173,40.91221618652344,-74.01078033447266,40.91221237182617

-73.92140960693358,40.76670837402344,-73.91441345214845,40.764686584472656

-73.92138671875,40.76667785644531,-73.93142700195312,40.771583557128906

-73.95548248291014,40.71404647827149,-73.94441223144531,40.71472930908203

-73.94529724121094,40.80818557739258,-73.93766784667969,40.821197509765625

-73.89087677001955,40.7464256286621,-73.87692260742188,40.75630569458008

-73.94670104980467,40.79732131958008,-73.9376449584961,40.80451583862305

-73.96315002441406,40.69382858276367,-73.956787109375,40.680530548095696

-73.89682006835938,40.74612808227539,-73.88862609863281,40.752723693847656

-73.82991790771484,40.713768005371094,-73.83494567871094,40.70729064941406

-73.9055404663086,40.77252578735352,-73.8953628540039,40.76896286010742

-73.941650390625,40.81829452514648,-73.950927734375,40.82603073120117

-73.93252563476562,40.85680389404297,-73.93136596679686,40.856117248535156

-73.95282745361328,40.808353424072266,-73.94914245605469,40.80290985107422

-73.904052734375,40.87870788574219,-73.89696502685547,40.90113067626953

-74.02134704589844,40.647010803222656,-74.00405883789062,40.65459442138672

-73.95098876953125,40.68049621582031,-73.9539566040039,40.69042205810547

-73.84967041015625,40.72400665283203,-73.83512878417969,40.70719909667969

-73.9466781616211,40.80628967285156,-73.93624877929686,40.79925155639648

-73.98682403564453,40.70245742797852,-73.97278594970702,40.69290161132813

-73.91205596923827,40.7754020690918,-73.89364624023438,40.76850509643555

-73.9617462158203,40.71377944946289,-73.98593139648438,40.71804809570313

-73.94091033935547,40.69868087768555,-73.94107818603516,40.6828498840332

-73.84423828125,40.72149658203125,-73.8086929321289,40.73440170288085

-73.89108276367188,40.74691009521485,-73.87848663330078,40.7494010925293

-73.84487915039062,40.75502395629883,-73.87222290039062,40.77399063110352

-73.87079620361328,40.73346328735352,-73.87014770507811,40.73357391357422

-73.94847869873048,40.81386184692383,-73.94107055664062,40.81884002685547

** subset of the data

I found following question in stackoverflow but not really sure if thats the correct approach.
Haversine Formula in Python (Bearing and Distance between two GPS points)

Update: So far solution

import math



    def getPoints(lon, lat):

        radius = 1800 # in feet (not sure if this is the right approach)

        N = 360 



        # generate points

        circlePoints = 

        for k in range(N):

            angle = math.pi*2*k/N

How important is accuracy, especially near the poles of Earth?

The easy thing to do would be to work out the number of feet per degree of latitude and longitude at your central point. Then for each point, you calculate the latitude and longitude differences from your central point in degrees, an convert them to feet using the conversion factor that is correct at the central point. Then you compute the distance in feet as sqrt(latFeet^2 + longFeet^2).

The latitude/foot conversion factor will be constant everywhere (1 Earth circumference / 360 degrees of latitude), but the longitude/foot conversion factor will change as your latitude changes. If you draw a diagram and do some trigonometry, you can see that the distance around the (assumed spherical) Earth at a given latitude is 2 * Pi * Earth Radius * sin(90 degrees - abs(latitude)), and dividing that by 360 degrees of latitude gives you your distance per degree.

The approximation that 1 degree of latitude or longitude is the same distance in feet over the area you are working in breaks down at the poles, but if you don't have to operate near the poles, and if you don't care about the oblateness of the Earth, it should hold relatively well over distances of 1000 feet.