76 lines
2.0 KiB
JavaScript
76 lines
2.0 KiB
JavaScript
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import path from 'path';
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import mapnik from 'mapnik';
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import SphericalMercator from '@mapbox/sphericalmercator';
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// config file with connection details
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const config = require('../../config.json')
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const DATASOURCE_CONFIG = {
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'dbname': config.database.dbname,
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'user': config.database.user,
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'password': config.database.password,
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'port': config.database.port,
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'geometry_field': 'geometry_geom',
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'extent' : '-20005048.4188,-9039211.13765,19907487.2779,17096598.5401',
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'srid': 3857,
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'type': 'postgis'
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}
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const TILE_SIZE = 256
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const TILE_BUFFER_SIZE = 64
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const PROJ4_STRING = '+proj=merc +a=6378137 +b=6378137 +lat_ts=0.0 +lon_0=0.0 +x_0=0.0 +y_0=0 +k=1.0 +units=m +nadgrids=@null +wktext +no_defs +over';
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// register datasource adapters for mapnik
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if (mapnik.register_default_input_plugins) mapnik.register_default_input_plugins();
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const mercator = new SphericalMercator({
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size: TILE_SIZE
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});
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function get_bbox(params){
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const { z, x, y } = params
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const int_z = parseInt(z);
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const int_x = parseInt(x);
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const int_y = parseInt(y);
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if (!int_x || !int_y || !int_z){
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console.error("Missing x or y or z")
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return {error:'Bad parameter'}
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}
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return mercator.bbox(
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int_x,
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int_y,
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int_z,
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false,
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'900913'
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);
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}
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function render_tile(bbox, table_def, style_def, cb){
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const map = new mapnik.Map(TILE_SIZE, TILE_SIZE, PROJ4_STRING);
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map.bufferSize = TILE_BUFFER_SIZE;
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const layer = new mapnik.Layer('tile', PROJ4_STRING);
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const conf = Object.assign({table: table_def}, DATASOURCE_CONFIG)
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const postgis = new mapnik.Datasource(conf);
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layer.datasource = postgis;
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layer.styles = style_def
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map.load(
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path.join(__dirname, '..', 'map_styles', 'polygon.xml'),
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{ strict: true },
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function(err, map){
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if (err) throw err
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map.add_layer(layer)
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const im = new mapnik.Image(map.width, map.height)
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map.extent = bbox
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map.render(im, cb);
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}
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)
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}
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export { get_bbox, render_tile };
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