Remove dependency on geopy

[danielolsen]

Purpose

Reduce number/scope of required dependencies. geopy is "a Python client for several popular geocoding web services. geopy makes it easy for Python developers to locate the coordinates of addresses, cities, countries, and landmarks across the globe using third-party geocoders and other data sources." We are using it to calculate the distance between two points.

What is the code doing

In distance.py, great_circle_distance takes a series with {from_lat, from_lon, to_lat, to_lon} and returns the distance between the two points. As far as I can tell, it's used only from within PostREISE. I've refactored it to use the haversine function/formula instead, and deleted the geopy import and requirements.

Validation

Over our entire grid, the maximum length difference between vincenty and haversine methods is 0.4 miles, for a 211 mile line. The largest relative difference appears to be 0.4% on a zero-length line (floating point cruft?).

(run with develop):

>>> from powersimdata.input.grid import Grid
>>> from powersimdata.utility.distance import haversine
>>> from powersimdata.utility.distance import great_circle_distance
>>> usa = Grid(['USA'])
Reading bus.csv
Reading plant.csv
Reading gencost.csv
Reading branch.csv
Reading dcline.csv
Reading sub.csv
Reading bus2sub.csv
Reading zone.csv
>>> branch = usa.branch
>>> branch["haversine"] = branch.apply(lambda x: haversine((x.from_lat, x.from_lon), (x.to_lat, x.to_lon)), axis=1)
>>> branch["gcd"] = branch.apply(great_circle_distance, axis=1) / 1.60934
>>> (branch.haversine - branch.gcd).abs().max()
0.42182497103240735
>>> (branch.haversine - branch.gcd).abs().idxmax()
96179
>>> branch.loc[96179]
from_bus_id            2030399
to_bus_id              2040783
r                     0.000895
x                     0.023936
b                      9.76203
rateA                  4235.96
rateB                        0
rateC                        0
ratio                        0
angle                        0
status                       1
angmin                       0
angmax                       0
Pf                    -1071.49
Qf                     -312.61
Pt                     1081.59
Qt                     -438.85
mu_Sf                        0
mu_St                        0
mu_angmin                    0
mu_angmax                    0
branch_device_type        Line
interconnect           Western
from_zone_id               208
to_zone_id                 209
from_zone_name          Nevada
to_zone_name           Arizona
from_lat               36.0875
from_lon              -115.051
to_lat                 36.9047
to_lon                -111.389
haversine              211.077
gcd                    211.499
Name: 96179, dtype: object
>>> ((branch.haversine - branch.gcd) / branch.gcd).abs().max()
0.003719583059931294
35428
>>> branch.loc[32428]
from_bus_id                   25583
to_bus_id                     25587
r                           0.00023
x                          0.001164
b                                 0
rateA                             0
rateB                             0
rateC                             0
ratio                             0
angle                             0
status                            1
angmin                            0
angmax                            0
Pf                                0
Qf                                0
Pt                                0
Qt                                0
mu_Sf                             0
mu_St                             0
mu_angmin                         0
mu_angmax                         0
branch_device_type             Line
interconnect                Eastern
from_zone_id                     20
to_zone_id                       20
from_zone_name        Georgia South
to_zone_name          Georgia South
from_lat                    31.6505
from_lon                   -84.0929
to_lat                      31.6505
to_lon                     -84.0929
haversine                         0
gcd                               0
Name: 32428, dtype: object

Time to review

5 minutes.

[jenhagg]

Could we use a constant here? mi_to_km = 1.60934

[danielolsen]

Done.

[jenhagg]

Awesome, thanks for cleaning this up.

[rouille]

Thanks for cleaning this up