@ugrc/layer-selector/src/TileInfo.js

This is a react component for adding a quick base map selector with a happy path for using [UGRC's Discover Service](https://gis.utah.gov/discover).

/**
 * Creates the default TileInfo constructor object for appliance layers.
 * @private
 * @returns {object} The least common denominator constructor object for appliance layers.
 */
const createDefaultTileInfo = (LOD) => {
  const tileSize = 256;
  const earthCircumference = 40075016.685568;
  const inchesPerMeter = 39.37;
  const initialResolution = earthCircumference / tileSize;

  const dpi = 96;
  const maxLevel = 20;
  const squared = 2;
  const lods = [];

  for (let level = 0; level <= maxLevel; level++) {
    const resolution = initialResolution / Math.pow(squared, level);
    const scale = resolution * dpi * inchesPerMeter;

    lods.push(
      new LOD({
        level: level,
        scale: scale,
        resolution: resolution,
      }),
    );
  }

  return {
    dpi: dpi,
    size: tileSize,
    origin: {
      x: -20037508.342787,
      y: 20037508.342787,
    },
    spatialReference: {
      wkid: 3857,
    },
    lods: lods,
  };
};

export { createDefaultTileInfo };