open-building-vt-generator

This module is to convert csv files of Google's building data in Africa to GeoJSON files.

Download

First of all, download all of building data by commandline.

gsutil cp -R gs://open-buildings-data/v1/polygons_s2_level_4_gzip .

The total size of files is 46GB for 135 files.

Extract .csv.gz to .csv

find ./polygons_s2_level_4_gzip -type f -name "*.gz" -exec gunzip {} \;

The total size of files after extracting is 129.5GB

Convert .csv to GeoJSON

• Installation

git clone git@github.com:watergis/google-building-csv2geojson.git
cd google-building-csv2geojson
npm i

• Convert

Modify building-csv2geojson.test.js

const { BuidlingCsv2GeoJSON} = require('../src/index');
const path = require('path');

(() => {
    // specify the directory where stored csv files
    const inputDir = path.resolve(__dirname, './data')
    // specify the directory where export to
    const outputDir = path.resolve(__dirname, './output')
    const csv2geojson = new BuidlingCsv2GeoJSON(inputDir, outputDir);
    csv2geojson.convert();
})();

npm run convert

generate vector tiles by tippecanoe

• if you just want to convert few GeoJSON files...

tippecanoe -P --no-feature-limit --no-tile-size-limit --force --minimum-zoom=15 --maximum-zoom=15 --base-zoom=15 --hilbert -l "open-buildings" -o open-buildings.mbtiles $(find ./tests/output/*.geojson)

This might take very long time to generate mbtiles if the number of GeoJSON is too much.

• if you want to convert in the entire Africa...

Modify geojson2mbtiles.test.js

const { GeoJSON2mbtiles}  = require('../src/index');
const path = require('path');

(async () => {
    const parentDir = __dirname;
    // specify the GeoJSON directory path.
    const inputDir = path.resolve(parentDir, './output')
    // specify the mbtiles directory path to export
    const outputDir = path.resolve(parentDir, './mbtiles')
    const geojson2mbtiles = new GeoJSON2mbtiles(inputDir, outputDir);
    await geojson2mbtiles.convert();
})();

npm run generate

Finally, you can merge all of mbtiles into one.

tile-join --force -o open-buildings.mbtiles --maximum-zoom=15 --minimum-zoom=15 --no-tile-size-limit $(find ./tests/mbtiles/*.mbtiles)

License

This source code's license is MIT, however the license of data is belong to Google. It is CC By 4.0 license. Please check their website.