getInterval_(resolution) {
    const centerLon = this.projectionCenterLonLat_[0];
    const centerLat = this.projectionCenterLonLat_[1];
    let interval = -1;
    const target = Math.pow(this.targetSize_ * resolution, 2);
    /** @type {Array<number>} **/
    const p1 = [];
    /** @type {Array<number>} **/
    const p2 = [];
    for (let i = 0, ii = this.intervals_.length; i < ii; ++i) {
      const delta = clamp(this.intervals_[i] / 2, 0, 90);
      // Don't attempt to transform latitudes beyond the poles!
      const clampedLat = clamp(centerLat, -90 + delta, 90 - delta);
      p1[0] = centerLon - delta;
      p1[1] = clampedLat - delta;
      p2[0] = centerLon + delta;
      p2[1] = clampedLat + delta;
      this.fromLonLatTransform_(p1, p1);
      this.fromLonLatTransform_(p2, p2);
      const dist = Math.pow(p2[0] - p1[0], 2) + Math.pow(p2[1] - p1[1], 2);
      if (dist <= target) {
        break;
      }
      interval = this.intervals_[i];
    }
    return interval;
  }
@param {number} resolution Resolution.
@return {number} The interval in degrees.
@private