Calculate the length of a polygon in python-CodePudding

I have a geopandas dataframe:

    lon           lat         geometry
0   31.269899   30.072927   POINT (30.07293 31.26990)
1   31.269413   30.073965   POINT (30.07397 31.26941)
2   31.268751   30.073629   POINT (30.07363 31.26875)
3   31.269287   30.073505   POINT (30.07351 31.26929)
4   31.269081   30.074694   POINT (30.07469 31.26908)

I created a polygon out of all of those points like this:

import geopandas as gpd
from shapely.geometry import Point, Polygon

gdf = gpd.GeoDataFrame(df,geometry = gpd.points_from_xy(df['lat'],df['lon']))
points = [x for x in gdf.geometry]
polygon = Polygon([[p.x, p.y] for p in points])
print(polygon)

The output is a polygon:

POLYGON ((30.072927474975586 31.269899368286133, 30.073965072631836 31.269412994384766, 30.07362937927246 31.26875114440918, 30.073505401611328 31.269287109375, 30.07469367980957 31.269081115722656, 30.073972702026367 31.269569396972656, 30.074140548706055 31.269651412963867, 30.07431983947754 31.26882553100586,...)

How can I get the length in meters? to get the distance between the first retailer for example and the last retailer on the map, so that it takes a shape of a line that you can measure.

I tried this code:

polygon.length * 0.000621371

It gave : 5.04009394506436e-05

Which is wrong.

What am I doing wrong here guys?

CodePudding user response：

How can I get the length in meters?

The unit distance between coordinates (lat, lon) is kilometers so to convert in meters just multiply by 1000:

>>> polygon.length * 1000
5.592554141703987  # meters

polygon.length * 0.000621371

Do you want the distance in meters or miles?

CodePudding user response：

Another way to do it is using geopy and it's function called distance, adding some changes to your code. geopy distance documentation

Usage:

geopy.distance.distance([from.lon, from.lat], [to.lon, to.lat]).km

Not sure if there's a built-in function to convert to meters, but having kilometers it should be easy to do.