Created
October 27, 2019 12:12
-
-
Save binarymason/08a65c8b70b2e34d02445c3167f723b9 to your computer and use it in GitHub Desktop.
Get the closest web mercator zoom for a raster input
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| import math | |
| import sys | |
| import rasterio | |
| from rasterio.warp import (calculate_default_transform, transform) | |
| CHUNK_SIZE = 256 | |
| def get_zoom(input, dst_crs="EPSG:3857"): | |
| with rasterio.drivers(): | |
| with rasterio.open(input) as src: | |
| # Compute the geographic bounding box of the dataset. | |
| (west, east), (south, north) = transform( | |
| src.crs, "EPSG:4326", src.bounds[::2], src.bounds[1::2]) | |
| affine, _, _ = calculate_default_transform(src.crs, dst_crs, | |
| src.width, src.height, *src.bounds, resolution=None) | |
| # grab the lowest resolution dimension | |
| resolution = max(abs(affine[0]), abs(affine[4])) | |
| return int(round(math.log((2 * math.pi * 6378137) / | |
| (resolution * CHUNK_SIZE)) / math.log(2))) | |
| if __name__ == "__main__": | |
| print(get_zoom(sys.argv[1])) |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment