function getLayerVisConfig(layerType, numDataPoints, segmentGroupId) {
  let colors;
  switch (layerType) {
    case 'heatmap':
      colors = HEATMAP_COLORS[segmentGroupId];
      break;
    case 'hexagonId':
      colors = DIVERGING_COLORS;
      break;
  }
  let opacity;
  switch (layerType) {
    case 'heatmap':
      opacity = 0.8;
      break;
    case 'hexagonId':
      opacity = 0.5;
      break;
  }
  return {
    opacity,
    colorRange: {
      colors,
    },
    radius: 10,
  };
}
@param {String} layerType kepler layer type
@param {Number} numDataPoints number of datapoints in a layer (post filtering)
@param {Number} segmentGroupId 0 or 1, which segment group this layer represents
@returns visConfig field of kepler config