geodot 0.1.3

Download satellite map tiles from the command line or as a Python library

geodot

geodot downloads satellite map tiles and can be used as a CLI or as a library from Python, JavaScript, and Rust.

Tiles are saved as:

{out}/tiles/{z}/{x}/{y}.jpg
{out}/manifest.json

Install

cargo install geodot
npm install -g @geodot/cli
npm install @geodot/lib
pip install geodot

Run without installing globally:

npx -y @geodot/cli -x 37.6504907 -y 55.7303 -z 18 -c 1 -r 1
uvx geodot -x 37.6504907 -y 55.7303 -z 18 -c 1 -r 1
cargo install geodot && geodot -x 37.6504907 -y 55.7303 -z 18 -c 1 -r 1

During local development:

python -m pip install -e '.[test]'
npm test
cargo test --manifest-path rust/Cargo.toml

Lint and format checks:

python -m pip install -e '.[test,dev]'
ruff format --check python
ruff check python

npm install
npm run format:check
npm run lint

cargo fmt --manifest-path rust/Cargo.toml -- --check
cargo clippy --manifest-path rust/Cargo.toml --all-targets -- -D warnings

CLI

geodot -x 37.6504907 -y 55.7303 -z 18 -c 3 -r 3 -o data -j 16

geodot -x 37.6504907 -y 55.7303 --x2 37.652 --y2 55.7297 -z 18 -o data

geodot -p "37.6504,55.7304;37.6520,55.7304;37.6520,55.7297;37.6504,55.7297" -z 18 -o data

geodot --geojson area.geojson -z 18 -o data

geodot --geojson https://example.com/area.geojson -z 18 -o data

Flag	Default	Description
-x, --lon	37.6504907	Top-left longitude
-y, --lat	55.7303	Top-left latitude
--x2, --bottom-right-lon	none	Bottom-right longitude
--y2, --bottom-right-lat	none	Bottom-right latitude
-p, --polygon	none	Closed area as lon,lat;lon,lat;lon,lat
-g, --geojson	none	GeoJSON Polygon, Feature, or FeatureCollection file path or URL
-z, --zoom	18	Zoom level
-c, --cols	3	Tile columns to the right of the top-left tile
-r, --rows	3	Tile rows downward from the top-left tile
-o, --out	data	Output directory
-j, --jobs	16	Concurrent downloads

Output

For -o data, a 3 by 3 download at zoom 18 writes files like this:

data/
├── manifest.json
└── tiles/
    └── 18/
        └── 158488/
            └── 81979.jpg

JPEG bytes are written directly from the tile server without re-compression.

Tile images are always 256x256 pixels. geodot does not currently support other tile sizes.

manifest.json contains:

{
  "center": { "x": 158488, "y": 81979, "z": 18 },
  "tiles": [
    {
      "tile": { "x": 158488, "y": 81979, "z": 18 },
      "bounds": {
        "lat_min": 55.730012,
        "lon_min": 37.650146,
        "lat_max": 55.730793,
        "lon_max": 37.651520
      },
      "path": "data/tiles/18/158488/81979.jpg",
      "bytes": 12345
    }
  ],
  "failed": []
}

Selection Modes

geodot supports three tile selection modes:

1. Grid mode: -x/-y selects the top-left tile, then cols/rows expands right and down.
2. Rectangle mode: -x/-y is the top-left geographic coordinate and --x2/--y2 is the bottom-right geographic coordinate.
3. Polygon mode: -p/--polygon specifies a closed area as semicolon-separated lon,lat pairs. The closing edge is implicit.

Polygon downloads include tiles whose center or corners fall inside the polygon, plus tiles containing polygon vertices.

GeoJSON input uses the first Polygon geometry found in a Polygon, MultiPolygon, Feature, or FeatureCollection and uses its exterior ring as the download polygon.

Python API

from geodot import Coordinate, DownloadOptions, download, latlon_to_tile, tile_bounds, tile_grid, tile_grid_between, tile_grid_for_polygon

tile = latlon_to_tile(55.7303, 37.6504907, 18)
bounds = tile_bounds(tile)
tiles = tile_grid(55.7303, 37.6504907, zoom=18, cols=3, rows=3)
rectangle = tile_grid_between(55.7303, 37.6504907, 55.7297, 37.652, zoom=18)
polygon = tile_grid_for_polygon([
    Coordinate(lon=37.6504, lat=55.7304),
    Coordinate(lon=37.6520, lat=55.7304),
    Coordinate(lon=37.6520, lat=55.7297),
    Coordinate(lon=37.6504, lat=55.7297),
], zoom=18)

report = download(DownloadOptions(
    lat=55.7303,
    lon=37.6504907,
    bottom_right_lat=55.7297,
    bottom_right_lon=37.652,
    zoom=18,
    cols=3,
    rows=3,
    out="data",
    jobs=16,
    geojson=None,
))

JavaScript API

import { download, latlonToTile, tileBounds, tileGrid, tileGridBetween, tileGridForPolygon } from '@geodot/lib';

const tile = latlonToTile(55.7303, 37.6504907, 18);
const bounds = tileBounds(tile);
const tiles = tileGrid(55.7303, 37.6504907, 18, 3, 3);
const rectangle = tileGridBetween(55.7303, 37.6504907, 55.7297, 37.652, 18);
const polygon = tileGridForPolygon([
  { lon: 37.6504, lat: 55.7304 },
  { lon: 37.6520, lat: 55.7304 },
  { lon: 37.6520, lat: 55.7297 },
  { lon: 37.6504, lat: 55.7297 },
], 18);

const report = await download({
  lat: 55.7303,
  lon: 37.6504907,
  bottomRightLat: 55.7297,
  bottomRightLon: 37.652,
  zoom: 18,
  cols: 3,
  rows: 3,
  out: 'data',
  jobs: 16,
  geojson: undefined,
});

Rust API

use geodot::{download, latlon_to_tile, tile_bounds, tile_grid, tile_grid_between, tile_grid_for_polygon, Coordinate, DownloadOptions};

#[tokio::main]
async fn main() -> anyhow::Result<()> {
    let tile = latlon_to_tile(55.7303, 37.6504907, 18);
    let bounds = tile_bounds(tile);
    let tiles = tile_grid(55.7303, 37.6504907, 18, 3, 3);
    let rectangle = tile_grid_between(55.7303, 37.6504907, 55.7297, 37.652, 18);
    let polygon = tile_grid_for_polygon(&[
        Coordinate { lon: 37.6504, lat: 55.7304 },
        Coordinate { lon: 37.6520, lat: 55.7304 },
        Coordinate { lon: 37.6520, lat: 55.7297 },
        Coordinate { lon: 37.6504, lat: 55.7297 },
    ], 18);

    let report = download(DownloadOptions {
        lat: 55.7303,
        lon: 37.6504907,
        bottom_right_lat: Some(55.7297),
        bottom_right_lon: Some(37.652),
        polygon: Vec::new(),
        zoom: 18,
        cols: 3,
        rows: 3,
        out: "data".into(),
        jobs: 16,
        geojson: None,
        tile_url_template: None,
    })
    .await?;

    Ok(())
}

Tile Math

Given tile { z: 18, x: 158488, y: 81979 }:

n = 2^z
lon_min = x / n * 360 - 180
lon_max = (x + 1) / n * 360 - 180
lat_max = atan(sinh(pi * (1 - 2y/n))) * 180/pi
lat_min = atan(sinh(pi * (1 - 2(y+1)/n))) * 180/pi

Tile bounds are returned as [lat_min, lon_min, lat_max, lon_max] fields.

Approximate resolution:

Zoom	m/px	Tile covers
18	0.34	86 x 86 m
16	1.36	347 x 347 m
14	5.45	1.4 x 1.4 km
10	86	22 x 22 km
8	345	88 x 88 km