Getting elevation for multiple lat long coordinates in Python

Question

I have seen the answer to Elevation info for multiple lat long coordinates and I would like to be able to do this with a python script instead. I cannot use Googles API because I have 8000 points. I have them as part of a .csv file which I import into pandas as a dataframe.

something like:

elevation_list = []

def elevation_function(df):
    for lat,long in zip(df.lat,df.lon):
          elevation_i = some_call_to_file(lat,long)
          elevation_list.append(elevation_i)

My coordinates span the western half of the US so Im not sure the function could be so simple. I have downloaded all SRTM90M resolution tiffs from this amazing person

Answer 1

Don't know if this is the simplest way, but it saves gathering elevation data. The USGS-National Map has a REST service that you can use to query elevation for lat/lon coords.

Service url: https://apps.nationalmap.gov/epqs/ (new) (old, deprecated as of March 1, 2023: https://nationalmap.gov/epqs/)

You can use pythons requests library and format your query string according to the service parameters. You need your input coordinates in NAD83 (lat/lon).

import requests
import urllib
import pandas as pd

# USGS Elevation Point Query Service
#url = r'https://nationalmap.gov/epqs/pqs.php?'
#new 2023:
url = r'https://epqs.nationalmap.gov/v1/json?'

# coordinates with known elevation 
lat = [48.633, 48.733, 45.1947, 45.1962]
lon = [-93.9667, -94.6167, -93.3257, -93.2755]
   
# create data frame
df = pd.DataFrame({
    'lat': lat,
    'lon': lon
})

def elevation_function(df, lat_column, lon_column):
    """Query service using lat, lon. add the elevation values as a new column."""
    elevations = []
    for lat, lon in zip(df[lat_column], df[lon_column]):
                
        # define rest query params
        params = {
            'output': 'json',
            'x': lon,
            'y': lat,
            'units': 'Meters'
        }
        
        # format query string and return query value
        result = requests.get((url + urllib.parse.urlencode(params)))
        #elevations.append(result.json()['USGS_Elevation_Point_Query_Service']['Elevation_Query']['Elevation'])
        #new 2023:
        elevations.append(result.json()['value'])

    df['elev_meters'] = elevations

elevation_function(df, 'lat', 'lon')
df.head()