NAIP Quadrangle Downloader


Four US Landmarks

The National Agriculture Imagery Program (NAIP) provides high-resolution aerial imagery of the United States to the public via an Amazon Web Services (AWS) S3 bucket.

Essentially, the US is broken into a grid of cells called quadrangles, and the images NAIP provides correspond to cells in this grid. Thus, to get an image containing a specific city or landmark, one must first figure out in which quadrangle it is located. This can be a little tedious to do by hand, so I made a function download_landmark() to automate it.

download_landmark('Statue of Liberty, NY')

This handy function can easily be incorporated into geographic information systems workflows. For example, although the image downloaded indeed contains the Statue of Liberty, it also has a lot more geography and you’d have to go searching through it to find the landmark. With only a bit more work, we can use the function not just to download the image but also extract a subset of it centered around the landmark. In fact, we’ll do it for a few landmarks in the code below which produces the image at the top of this page.

import rasterio
from rasterio.mask import mask as rio_mask
from matplotlib import pyplot as plt
from shapely.geometry import box
from pyproj import Proj
import numpy as np

places = [
    'Statue of Liberty, NY',
    'National Mall, Washington DC',
    'Hoover Dam, AZ',
    'Golden Gate Bridge, CA'
img_dir = 'naip/img'
mask_len = 1500 # meters
fig, axes = plt.subplots(2, 2, figsize = (10, 10))
axes = axes.flatten()

for i, place in enumerate(places):
    img_path, lat, lon = download_landmark(place, img_dir)
    with as src:

        ## Project landmark lat,lon
        proj = Proj(
        x,y = proj(lon, lat)

        ## Make mask centered at the landmark
        mask_shape = box(x-mask_len/2, y-mask_len/2, x+mask_len/2, y+mask_len/2)
        mask = {'type': 'Polygon', 'coordinates': [list(mask_shape.exterior.coords)]}

        ## Extract only the data within the mask
        img, transform = rio_mask(src, [mask], crop = True)
        img = np.moveaxis(img, 0, 2) # channels last

fig.savefig('four_us_landmarks.png', bbox_inches = 'tight')

The script as well as a tutorial explaining it can be found on my GitHub.