geojson-to-tile-images

This is a Node.js package that allows you to convert GeoJSON to tile images.

Installation

npm install geojson-to-tile-images

Usage

import GeoJSONToTileImages from 'geojson-to-tile-images';
import * as fs from 'fs';

const geoJSON = {
	"type": "FeatureCollection",
	"features": [
		{
			"type": "Feature",
			"properties": {
				"fill": "red",
				"fill-opacity": 0.75
			},
			"geometry": {
				"coordinates": [
					[
						[
							-77.01321657760587,
							38.89222010921145
						],
						[
							-77.01321657760587,
							38.88703541565883
						],
						[
							-77.00512620244129,
							38.88703541565883
						],
						[
							-77.00512620244129,
							38.89222010921145
						],
						[
							-77.01321657760587,
							38.89222010921145
						]
					]
				],
				"type": "Polygon"
			}
		},
		{
			"type": "Feature",
			"properties": {
				"text": "Washington DC",
				"font-size": 16,
				"font-weight": "bold",
				"color": "#333333",
				"text-anchor": "middle",
				"dominant-baseline": "middle"
			},
			"geometry": {
				"type": "Point",
				"coordinates": [-77.009, 38.8895]
			}
		}
	]
};

(async () => {
	const image = await GeoJSONToTileImages(geoJSON, [15, 9374, 12536], {
		"backgroundColor": {
			"r": 0,
			"g": 0,
			"b": 0,
			"alpha": 0.5
		},
		"size": 256
	});
	fs.writeFileSync('image.png', image);
})();

Supported GeoJSON Types

• Polygon
• LineString
• MultiLineString
• Point (for text rendering)

Supported GeoJSON Properties

Polygon

• fill - Fill color (default: "black")
• fill-opacity - Fill opacity 0-1 (default: 1.0)

LineString / MultiLineString

• stroke - Stroke color (default: "black")
• stroke-opacity - Stroke opacity 0-1 (default: 1.0)
• stroke-width - Stroke width in pixels (default: 1)

Point (Text)

• text - Text content to display (required)
• font-family - Font family (default: "Arial")
• font-size - Font size in pixels (default: 14)
• font-weight - Font weight: "normal", "bold", or 100-900 (default: "normal")
• color - Text color (default: "black")
• opacity - Text opacity 0-1 (default: 1.0)
• text-anchor - Horizontal alignment: "start", "middle", "end" (default: "middle")
• dominant-baseline - Vertical alignment: "top", "middle", "bottom" (default: "middle")

License

MIT