Edit in JSFiddle

const base = 'https://image.maps.api.here.com/mia/1.6/mapview?';
const params = {
	c: '19.4346%2C-99.1601', //Latitude, Longitude
  t: 2, //Map style. 2 = terrain
  app_id: 'devportal-demo-20180625',
  app_code: '9v2BkviRwi9Ot26kp2IysQ'
}

const url = base + Object.keys(params).map(key => key + '=' + params[key]).join('&')
console.log(url);
document.querySelector('img').src = url