Vector tile generator

A repository to demo and test a few methods of generating vector tiles

Installation

Local database

The testing was done using a local database server installed on MacOS using homebrew.

brew install postgresql postgis

After these are installed you may need to run some steps to ensure the pg commands are available in your shell. See guidance online for install such as How to install PostgreSQL on a Mac with HomebrewIn some cases there can be conflicts with the default MacOS database files location, but you can initialise the data directory in a different location.

pg_ctl -D postgres start

Setup packages

The node packages are installed using npm. The package.json file contains the dependencies.

npm install

Tippecanoe

The tippecanoe method is using node but is a wrapper around a local install of tippecanoe. Tippecanoe is a command line utility for converting GeoJSON to vector tiles. It can also be installed using homebrew (or various other methods).

brew install tippecanoe

GDAL

In part of the process we generate a GeoJSON file from a CSV exported from the database. This is done using the ogr2ogr command line utility from the GDAL package. This can also be installed using homebrew.

brew install gdal

Instructions

The three different methods of generating tiles are tippecanoeBulk, vtPbfSequential and databaseSequential.

First take a copy of the sample environment file, rename to .env and update the values to match your local database and the layer you wish to convert to vector tiles. For example:

DB_TABLE=flood_risk_rivers_and_sea
DB_COLUMNS=prob_4band,suitabilit,pub_date,st_area_sh,st_perimet
MIN_ZOOM_LEVEL=4
MAX_ZOOM_LEVEL=14

When you are ready to try it out ensure you have a database running and the table you want to convert is available. Then run the following command:

node --max-old-space-size=24576 ./index.js tippecanoeBulk

Replace tippecanoeBulk with vtPbfSequential or databaseSequential to try the other methods.

Performance

Some basic timings were taken for the different methods.

Features	Method	Time
16	Tippecanoe	0.7s
16	vtPbf	1.7s
16	PostGIS	29.1s
1525731	Tippecanoe	449.6s