我正在阅读一个JS文件,用于将一个空间模型(.gml)从一个特定的投影转换为另一个投影。在以下代码中,":::"是什么意思?
_getTransformation(projectionFrom, projectionTo) {
let cacheKey = `${projectionFrom}:::${projectionTo}`;
if (!this.transformations[cacheKey]) {
let from = this._getProjection(projectionFrom);
let to = this._getProjection(projectionTo);
this.transformations[cacheKey] = proj4(from, to);
}
return this.transformations[cacheKey];
}
projectionFrom + ":::" + projectionTo
。 - Eddie