1. 降维可以在压缩数据的同时让信息损失最小化； 2. 理解几百个维度的数据结构很困难，两三个维度的数据通过可视化更容易理解。(1. Dimensionality reduction can minimize information loss while compressing data; 2. It is difficult to understand the data structure of hundreds of dimensions, and it is easier to u