README.md

abaculus

a small block of stone, tile, glass, or other material used in the construction of a mosaic

or,

a library for creating static maps from tiles based on center or corner lng,lat coordinates. Uses node-mapnik to stitch tiles together.

Looking to create high res images of maps? Abaculus was written for use in Mapbox Studio and you can use Mapbox Studio to create and export high resolution images -- see https://www.mapbox.com/guides/print/ for more information. You can even use that utility from the command line.

usage

Usage and example formatting below, or see the tests for a more robust example with a getTile function.

input:

scale: integer between 1-4 and sets resolution (scale: 1 is 72dpi, scale: 4, is 288dpi)

zoom: zoom level

[w, s, e, n]: the bounding box for the west (lat val), south (lng val), east (lat val), north (lng val) for the desired area

x: longitude coordinate

y: latitude coordinate

width and height: desired pixel bounds for a map with a center coordinate. Will be multiplied by scale to maintain resolution.

format (optional): png or jpeg, default is png.

quality (optional): when used with jpeg 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 none.

tileSize (optional, defaults to 256): Specifies input size of tiles used in getTile function.

getTile: a function that returns a tile buffer (png or otherwise) and headers given z, x, y, and a callback, such as from tilelive-vector or this test function.

limit (optional): max width or height of generated image in pixels. Default is 19008.

// Calculate image bounds from W,S,E,N bounding box.
var params = {
	zoom: {zoom},
	scale: {scale}
    bbox: [{w}, {s}, {e}, {n}],
    format: {format},
    quality: {quality},
	tileSize: {tileSize},
    getTile: function(z, x, y, callback){
		// do something
		return callback(null, buffer, headers);
	},
	limit: {limit}
};

or

// Calculate image bounds from center lng,lat coordinates and
// pixel dimensions of final image (will be multipled by scale).
var params = {
	zoom: {zoom},
	scale: {scale}
    center: {
    	x: {x},
    	y: {y},
    	w: {width},
    	h: {height}
    },
    format: {format},
    quality: {quality},
	tileSize: {tileSize},
    getTile: function(z,x,y, callback){
		// do something
		return callback(null, buffer, headers);
	},
	limit: {limit}
};

usage:

abaculus(params, function(err, image, headers){
	if (err) return err;
	// do something with image
});

output:

an image of desired resolution for the selected area.