text: /**
   * Takes a bounding box and returns a new bounding box with a size expanded or contracted
   * by a factor of X.
   *
   * @module turf/size
   * @category measurement
   * @param {Array<number>} bbox a bounding box
   * @param {number} factor the ratio of the new bbox to the input bbox
   * @return {Array<number>} the resized bbox
   * @example
   * var bbox = [0, 0, 10, 10]
   *
   * var resized = turf.size(bbox, 2);
   *
   * var features = {
   *   "type": "FeatureCollection",
   *   "features": [
   *     turf.bboxPolygon(bbox),
   *     turf.bboxPolygon(resized)
   *   ]
   * };
   *
   * //=features
   */
  module.exports = function(bbox, factor){
    var currentXDistance = (bbox[2] - bbox[0]);
    var currentYDistance = (bbox[3] - bbox[1]);
    var newXDistance = currentXDistance * factor;
    var newYDistance = currentYDistance * factor;
    var xChange = newXDistance - currentXDistance;
    var yChange = newYDistance - currentYDistance;
  
    var lowX = bbox[0] - (xChange / 2);
    var lowY = bbox[1] - (yChange / 2);
    var highX = (xChange / 2) + bbox[2];
    var highY = (yChange / 2) + bbox[3];
  
    var sized = [lowX, lowY, highX, highY];
    return sized;
  }
  