If the file is thin, some contents will be compressed and some details will inevitably be lost. If there is not enough storage, it is recommended not to lose weight as much as possible.

Data is the expression and carrier of information, which can be symbols, characters, numbers, sounds, images, videos and so on. Data and information are inseparable. Data is the manifestation of information, and information is the connotation of data. Data itself is meaningless, and only when it affects the behavior of entities can data become information.

In computer science, data refers to all symbolic media that can be input into a computer and processed by a computer program. It is the general name of numbers, letters, symbols and analog quantities used for input into electronic computers for processing. It is the most basic element of geographic information system, and there are many kinds.