Edit in JSFiddle

'use strict';
var grid = [];
var _width = 75;
var _height = 75;

window.run = function (land) {
    var r = radial();
    var b = document.getElementById("radial");
    b.innerHTML = '';
    b.style.display = 'inline-block';
    for (var x = 0; x < r.length; x++) {
        var e = document.createElement('div');
        for (var y = 0; y < r[0].length; y++) {
            var d = document.createElement('div');
            if (land) {
                if (r[x][y] < 0.55) {
                    d.style.backgroundColor = '#0000ff';
                } else {
                    d.style.backgroundColor = '#00ff00';
                }
            } else {
                var c = ~~ (r[x][y] * 255);
                d.style.backgroundColor = 'rgb(' + c + ',' + c + ',' + c + ')';
            }

            d.innerHtml = '&nbps;'
            d.style.width = '5px';
            d.style.height = '5px';
            d.style.float = 'left'
            e.appendChild(d);
        }
        b.appendChild(e);
        //b.innerHtml += '<br>'
    }
}

function radial() {
    var grid = [];
    var _its = 2000;
    var _life = 20;
    var _edgex = _width * 0.15;
    var _edgey = _height * 0.15;
    var _blur1 = 0.85;
    var _blur2 = 0.77;

    for (var x = 0; x < _width; x++) {
        grid[x] = [];
        for (var y = 0; y < _height; y++) {
            grid[x][y] = 0;
        }
    }

    for (var i = 0; i < _its; i++) {
        var x = ~~ (Math.random() * (_width - (_edgex * 2)) + _edgex);
        var y = ~~ (Math.random() * (_height - (_edgey * 2)) + _edgey);

        for (var j = 0; j < _life; j++) {
            x += Math.round(Math.random() * 2 - 1);
            y += Math.round(Math.random() * 2 - 1);

            if (x < 1 || x > _width - 2 || y < 1 || y > _height - 2) continue;

            var hood = _next(x, y);

            for (var k = 0; k < hood.length; k++) {
                if (grid[hood[k][0]][hood[k][1]] < grid[x][y]) {
                    x = hood[k][0];
                    y = hood[k][1];
                    continue;
                }
            }

            grid[x][y]++;
        }
    }

    return _normalize(grid);

    function _range(min, max) {
        return~~ ((max - min) * Math.random() + min);
    }

    function _next(x, y) {
        var result = [];

        for (var a = -1; a <= 1; a++) {
            for (var b = -1; b <= 1; b++) {
                if (a || b && (x + a >= 0 && x + a < _width && y + b >= 0 && y + b < _height)) {
                    result.push([x + a, y + b]);
                }
            }
        }

        return _shuffle(result);
    };

    function _shuffle(o) { //v1.0
        for (var j, x, i = o.length; i; j = Math.floor(Math.random() * i), x = o[--i], o[i] = o[j], o[j] = x);
        return o;
    };

    function _normalize(grid) {
        var max = 0;
        var min = 10000000;
        for (var x = 0; x < grid.length; x++) {
            for (var y = 0; y < grid[0].length; y++) {
                if (x == 0 || x == _width - 1 || y == 0 || y == _height - 1) grid[x][y] *= 0.77;
                else if (x == 1 || x == _width - 2 || y == 1 || y == _height - 2) grid[x][y] *= 0.85;
                var g = grid[x][y];
                if (g > max) max = g;
                if (g < min) min = g;
            }
        }

        for (var x = 0; x < grid.length; x++) {
            for (var y = 0; y < grid[0].length; y++) {
                grid[x][y] = (grid[x][y] - min) / (max - min);
            }
        }
        return grid;
    }
}

run();
<button type="button" onclick="run(false)">Show me as noise!</button>
<button type="button" onclick="run(true)">Show me as land!</button>
<br>
<br>
<div id="radial"></div>