@carto/cartonik

    0.9.1 • Public • Published

    Cartonik 🌍

    CircleCI

    Render maps with @carto/mapnik

    🚀 Features

    • Render tiles from a Mapnik XML
    • Support several formats: png, jpeg, grid.json, mvt, etc..
    • Support traditional mapnik datasources: shape, postgis, gdal, ogr, etc..
    • Render static images from tiles based on center (long, lat) or bounding box (east, south, west, north) coordinates.
    • Optimized for high-performance services

    📦 Installation

    Cartonik requires Node.js 12

    npm install @carto/cartonik

    🌐 Render tiles

    const { rendererFactory } = require('@carto/cartonik')
    
    const renderer = rendererFactory({ xml: '<Map>...</Map>' })
    const [ format, z, x, y ] = [ 'png', 0, 0, 0 ]
    
    const tile = await renderer.getTile(format, z, x, y)

    💻 Usage: rendererFactory(options)

    const options = { ... }
    const renderer = rendererFactory(options)

    📐 Renderer options

    • type: string (either raster or vector, default raster). Whether the renderer aims to render Mapnik Vector Tiles or traditional raster formats (png, utf).
    • xml: string (required). The Mapnik XML configuration.
    • base: string. Path to the folder where the datasource files are (e.g. shapefiles).
    • strict: boolean (default false). Enables mapnik strict mode.
    • bufferSize: number (default 256). Extra space, in pixels, surrounding the map size being rendered. This allows you to have text and symbols rendered correctly when they overlap the image boundary.
    • poolSize: number (default os.cpus().length). Max number of preloaded maps available for rendering.
    • poolMaxWaitingClients: number (default 32). Max number of waiting clients to acquire one of the preloaded maps.
    • tileSize: number (default 256). Size of the tile in pixels.
    • limits: object.
      • render: number (default 0 = disabled). Time in milliseconds to wait for the renderer to return a tile.
    • metrics: boolean (default false). Configure @carto/mapnik to gather statistics about rendering performance.
    • variables: object. A key-value dictionary to customize map configuration at render-time. Placeholders defined in xml (e.g. <PolygonSymbolizer fill="@water"/>) will be replaced with the values defined here (e.g. { water: 'blue' }).

    Raster renderer options (type = raster)

    • metatile: number (default 2). The number of tiles included in a metatile. One metatile generates a group of images at once in batches before separating them into the final tiles - this improves efficiency in various ways.
    • metatileCache: object.
      • timeout: number (default 1 minute). When the timeout fires, it removes the cached tiles.
      • deleteOnHit: boolean (default false). Removes the cached tile after delivered.
    • scale: number (default 1). Multiplier to scale up size-related properties of symbolizers.
    • resolution: number (default 4). When format = utf, the factor to scale down the tile size.

    Vector renderer options (type = vector)

    • gzip: boolean (default true). Compression method used to encoding a vector tile.

    🔍 Get information about the renderer

    const { rendererFactory } = require('@carto/cartonik')
    
    const renderer = rendererFactory({ xml: '<Map>...</Map>' })
    
    const stats = renderer.getStats()
    
    console.log(stats)
    //  Map { 'cache.png' => 1, 'pool.count' => 2, 'pool.used' => 1, 'pool.unused' => 1, 'pool.waiting' => 0 }

    🎆 Static images (previews)

    const { preview, rendererFactory } = require('@carto/cartonik')
    
    const renderer = rendererFactory({ xml: '<Map>...</Map>' })
    
    const { image } = await preview({
        center: {
            lng: -3.68529754,
            lat: 40.40197212
        },
        dimensions: {
            width: 200,
            height: 200
        },
        getTile: async function (format, x, y, z) {
            const { buffer } = await renderer.getTile(format, z, x, y)
            return { buffer }
        }
    })

    💻 Usage: preview(options)

    const options = { ... }
    const renderer = preview(options)

    📐 Preview options

    • getTile: function (required). Function to retrive the required tiles to build the preview image.
    • bbox: object. The bounding box for the west, south, east, and north coordinates of the requested area.
      • west: number. Longitude coordinate.
      • south: number. Latitude coordinate.
      • east: number. Longitude coordinate.
      • north: number. Latitude coordinate.
    • center: object. Point where the preview is centered. This option must be used along dimensions option.
      • lng: number. Long coordinate.
      • lat: number. Latitude coordinate.
    • dimensions: object. Preview's size in pixels. This options must be defined along center option and will be multiplied by scale to keep the resolution.
      • width: number.
      • heigth: number.
    • zoom: number default 0. The z cordinate, x and y will be calculated based on either bbox or center coordinates.
    • scale: number [1-4], default 1. Resolution (scale: 1 is 72dpi, scale: 4, is 288dpi).
    • format: string either png or jpg, default png.
    • quality: number. When used with jpg format, accepts 1-100 and defaults to 80. When used with png format, accepts 2-256 (# of colors to reduce the image to) and defaults to null.
    • limit: number default 19008. Max width or height of requested image in pixels. Default is 19008.
    • tileSize: number default 256. Size of tiles used in getTile function.
    • concurrency: number default 32. Number of concurrent calls to getTile. Useful to avoid map-pool exhaustion. Ideally, should match with poolSize (os.cpus().length) + poolMaxWaitingClients (32).

    🔢 Versioning

    We use SemVer for versioning. For the versions available, see the tags on this repository.

    👥 Contributors

    📃 License

    This project is licensed under the BSD 3-clause "New" or "Revised" License - see the LICENSE file for details.

    Keywords

    none

    Install

    npm i @carto/cartonik

    DownloadsWeekly Downloads

    20

    Version

    0.9.1

    License

    BSD-3-Clause

    Unpacked Size

    41 kB

    Total Files

    25

    Last publish

    Collaborators

    • felixpalmer
    • josmorsot
    • aaranadev
    • bbecquet
    • zbigg
    • eamadorp
    • juanra-carto
    • cartodb
    • alasarr
    • victor.velarde
    • shylpx
    • jaragon