export type FeaturesIndex = {
    byId: Map<string, GeoJSON.Feature>;
    byDataValue: Map<string, string>;
    byNormalizedValue: Map<string, string>;
};
/**
 * Creates an index for O(1) lookup instead of O(n) find()
 */
export declare const createFeaturesIndex: (features: GeoJSON.Feature[], mapType: string) => FeaturesIndex;