在地图管理结合图层管理和块管理，更加方便用户使用和节省存储空间。

Block management is combined with layer management in map management function in order to make user use the software more conveniently and save the storage space.

youdao

改进的内存管理：改善了内存的使用，所以有多个图层的大文件使用的内存比起2.1版本来说少得多。

Improved memory Management: memory use has been improved so that large documents with multiple layers use significantly less memory than in version 2.1.

youdao