PostGIS 矢量瓦片

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title: PostGIS 矢量瓦片
date: 2023-08-07
author: ac
tags:

vector tile
categories:
Database

Martin - 基于PostGIS的矢量瓦片服務(wù)器

1. 簡介

目前流行的矢量瓦片的切圖方案：

mapbox gl + tippecanoe ：v2收費，tippecanoe是mapbox官方推薦的矢量瓦片靜態(tài)生成工具，適用于大數(shù)據(jù)量場景，且不頻繁更新的空間數(shù)據(jù)；
openlayers + geoserver ：開源，使用geoserver的矢量瓦片擴展，增加矢量瓦片的輸出格式；
maplibre+ Martin +postgis ：開源，martin是矢量切片服務(wù)器，通過postgis的函數(shù)動態(tài)生成矢量瓦片。
maptiler：收費

mapbox v2 必須使用 access token 才能初始化 Map 對象。進行token計算，每月50000免費次數(shù)。

2. Martin

Martin是一個開源的PostGIS矢量切片服務(wù)器，可以從任何PostGIS表或視圖中創(chuàng)建MVT矢量切片，也可以從 PMTile 和MBTile文件中動態(tài)生成矢量瓦片，是使用 Rust編寫，針對切片速度和大流量進行了優(yōu)化，是極快且輕量級的切片服務(wù)器。

2.1 安裝

如果將Martin和PostgreSQL一起使用，PostGIS版本必須為v3.0+

Martin支持Linux、macOS、windows平臺和docker環(huán)境，本例采用windows環(huán)境。先從github上下載martin-Windows-x86_64 。解壓后會發(fā)現(xiàn)這兩個exe:

─martin-Windows-x86_64
  ├─martin.exe
  └─mbtiles.exe

windows平臺可以直接使用martin.exe來啟動切片服務(wù)器，可以先在命令行查看一下參數(shù)：

D:\tools\vectorTileTool\martin-Windows-x86_64>martin.exe --help
Blazing fast and lightweight tile server with PostGIS, MBTiles, and PMTiles support

Usage: martin.exe [OPTIONS] [CONNECTION]...

Arguments:
  [CONNECTION]...  Connection strings, e.g. postgres://... or /path/to/files

Options:
  -c, --config <CONFIG>
          Path to config file. If set, no tile source-related parameters are allowed
      --save-config <SAVE_CONFIG>
          Save resulting config to a file or use "-" to print to stdout. By default, only print if sources are auto-detected
  -s, --sprite <SPRITE>
          Export a directory with SVG files as a sprite source. Can be specified multiple times
  -k, --keep-alive <KEEP_ALIVE>
          Connection keep alive timeout. [DEFAULT: 75]
  -l, --listen-addresses <LISTEN_ADDRESSES>
          The socket address to bind. [DEFAULT: 0.0.0.0:3000]
  -W, --workers <WORKERS>
          Number of web server workers
  -b, --disable-bounds
          Disable the automatic generation of bounds for spatial PG tables
      --ca-root-file <CA_ROOT_FILE>
          Loads trusted root certificates from a file. The file should contain a sequence of PEM-formatted CA certificates
  -d, --default-srid <DEFAULT_SRID>
          If a spatial PG table has SRID 0, then this default SRID will be used as a fallback
  -p, --pool-size <POOL_SIZE>
          Maximum connections pool size [DEFAULT: 20]
  -m, --max-feature-count <MAX_FEATURE_COUNT>
          Limit the number of features in a tile from a PG table source
  -h, --help
          Print help
  -V, --version
          Print version

2.2 使用

本例pg安裝postgis是v3.3.3.1

martin連接pg可以用connection_string（命令行參數(shù)）和配置文件兩種形式。

PostgreSQL連接字符串的形式：

# martin.exe postgresql://user:password@host/db
D:\tools\vectorTileTool\martin-Windows-x86_64>martin.exe postgresql://postgres:123@127.0.0.1:5433/postgres
[2023-08-08T03:50:11Z INFO  martin] Starting Martin v0.8.7
[2023-08-08T03:50:11Z INFO  martin] Config file is not specified, auto-detecting sources
[2023-08-08T03:50:11Z INFO  martin::pg::pool] Connecting to postgresql://postgres:123@127.0.0.1:5433/postgres
[2023-08-08T03:50:11Z INFO  martin::pg::configurator] Discovered source zhujiang_river from table public.zhujiang_river with geom column (MULTIPOLYGON, SRID=4326)
[2023-08-08T03:50:11Z INFO  martin] Use --save-config to save or print Martin configuration.
[2023-08-08T03:50:11Z INFO  martin] Martin has been started on 0.0.0.0:3000.
[2023-08-08T03:50:11Z INFO  martin] Use http://0.0.0.0:3000/catalog to get the list of available sources.

配置文件的形式 config.yaml：

# Connection keep alive timeout [default: 75]
keep_alive: 75

# The socket address to bind [default: 0.0.0.0:3000]
listen_addresses: '127.0.0.1:3000'

# Number of web server workers
worker_processes: 8
# Database configuration. This can also be a list of PG configs.
postgres:
  # Database connection string. You can use env vars too, for example:
  #   $DATABASE_URL
  #   ${DATABASE_URL:-postgresql://postgres@localhost/db}
  connection_string: 'postgresql://postgres@localhost:5433/postgres?sslmode=disable&user=postgres&password=123'
  
  # Same as PGSSLCERT for psql
  #ssl_cert: './postgresql.crt'
  # Same as PGSSLKEY for psql
  #ssl_key: './postgresql.key'
  # Same as PGSSLROOTCERT for psql
  #ssl_root_cert: './root.crt'

  #  If a spatial table has SRID 0, then this SRID will be used as a fallback
  default_srid: 4326

  # Maximum connections pool size [default: 20]
  pool_size: 20

  # Limit the number of table geo features included in a tile. Unlimited by default.
  max_feature_count: 1000

  # Control the automatic generation of bounds for spatial tables [default: false]
  # If enabled, it will spend some time on startup to compute geometry bounds.
  disable_bounds: false

D:\tools\vectorTileTool\martin-Windows-x86_64>martin.exe -c config.yaml
[2023-08-08T03:54:43Z INFO  martin] Starting Martin v0.8.7
[2023-08-08T03:54:43Z INFO  martin] Using config.yaml
[2023-08-08T03:54:43Z INFO  martin::pg::pool] Connecting to postgresql://postgres@localhost:5433/postgres?sslmode=disable&user=postgres&password=123
[2023-08-08T03:54:43Z INFO  martin::pg::configurator] Discovered source zhujiang_river from table public.zhujiang_river with geom column (MULTIPOLYGON, SRID=4326)
[2023-08-08T03:54:44Z INFO  martin] Use --save-config to save or print Martin configuration.
[2023-08-08T03:54:44Z INFO  martin] Martin has been started on 127.0.0.1:3000.
[2023-08-08T03:54:44Z INFO  martin] Use http://127.0.0.1:3000/catalog to get the list of available sources.

本例采用的是配置文件的形式啟動服務(wù)器，服務(wù)地址是http://127.0.0.1:3000。

從啟動的日志可以看到Martin將所連接的pg庫中的zhujiang_river表發(fā)布為數(shù)據(jù)源。

Martin 會將所有表發(fā)布為數(shù)據(jù)源（如果它們至少有一個幾何列）。如果 SRID 為 0，則必須設(shè)置默認(rèn) SRID，否則該地理列/表將被忽略。所有非幾何表列都將發(fā)布為矢量切片要素標(biāo)簽（屬性）。

PostGIS 矢量瓦片,postgresql

打開目錄可以看到已發(fā)布的數(shù)據(jù)源：
PostGIS 矢量瓦片,postgresql

數(shù)據(jù)表的元數(shù)據(jù)是符合TileJSON 3.0.0標(biāo)準(zhǔn)的JSON文件。

TileJSON是表示地圖元數(shù)據(jù)的開放標(biāo)準(zhǔn)

2.3 mapbox

發(fā)布完數(shù)據(jù)源后，使用mapbox gl 來調(diào)用一下：

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <script src="https://unpkg.com/mapbox-gl@1.9.1/dist/mapbox-gl.js"></script>
    <link href="https://unpkg.com/mapbox-gl@1.9.1/dist/mapbox-gl.css"/>
    <style>
        #map{
            height: 100vh;
            width: 100%;
        }
    </style>
</head>
<body>
    <div id="map"></div>
    <script>
        
        const TIANDITU_URL = 'http://t0.tianditu.gov.cn';
        const tdtKey = "your_token";
        const tdtConfig = {
            code: 'tdt_img',
            name: '天地圖影像',
            source: {
                type: 'raster',
                tiles: [
                    `${TIANDITU_URL}/DataServer?T=img_w&x={x}&y={y}&l={z}&tk=${tdtKey}`
                ],
                tileSize: 256,
                minzoom: 0,
                maxzoom: 22
            },
            layer: {
                id: 'tdt-img-tiles',
                type: 'raster',
                minzoom: 0,
                maxzoom: 22,
                layout: { visibility: 'visible' }
            }
        }
        let map = new mapboxgl.Map({
            container:'map',
            style:{
                "version":8,
                "sources":{},
                "layers":[],
                glyphs: "mapbox://fonts/mapbox/{fontstack}/{range}.pbf",
            },
            center: [112.39747, 22.908823], // 廣東
            zoom: 8, // starting zoom 地圖初始的拉伸比例
            pitch: 0, // 地圖的角度，不寫默認(rèn)是0，取值是0-85度，一般在3D中使用
            bearing: 0, // 地圖的初始方向，值是北的逆時針度數(shù)，默認(rèn)是0，即是正北
            antialias: true, // 抗鋸齒，通過false關(guān)閉提升性能
            minZoom: 3,
            maxZoom: 17.36
        });
        map.on('load', () => {
            // 天地圖底圖加載
            addLayerConfig(tdtConfig);
            addMvt();
        });
        function addLayerConfig(layerConfig){
            const {code, source,layer} = layerConfig;
            map.addSource(code, source);
            const layerParams = {
                ...layer,
                source: code
            };
            // 添加圖層
            map.addLayer(layerParams);
        }
        function addMvt(){
            map.addLayer({
                id: 'lines',
                type: 'fill',
                source: {
                    type: 'vector',
                    url: 'http://localhost:3000/zhujiang_river'
                },
                'source-layer': 'zhujiang_river',
                paint: {
                	'fill-color': 'red'
                }
            });
        }
    </script>
</body>
</html>