MySQL的空间缓冲区调用中使用的度量单位是什么? [英] What is the unit of measurement used in MySQL's spatial Buffer call?

问题描述

Buffer 调用是格式为Buffer(g,d).

g是几何值(例如点，线串和多边形).

g is a geometry value (e.g. point, linestring, and polygon).

d是距离.

d使用什么度量单位? 米?里数?公里?

What unit of measurement is d using? Meters? Miles? Kilometers?

推荐答案

此处或任何空间分析功能中都没有单位.

There aren't units here, or in any of the spatial analysis functions.

这些功能通常与使用纬度和经度坐标的几何值一起使用，但是空间功能可以与来自任意网格坐标系的数据一起使用，并且服务器的功能对功能的本质一无所知特定的空间"被映射.

These functions are commonly used with geometriy values with coordinates using degrees latitude and longitude, but the spatial capabilities can be used with data from any arbitrary grid coordinate system, and the server's capabilities don't have any awareness of the nature of the particular "space" being mapped.

那么，距离将以单位"为单位.

The distance, then, would be in "units."

单位将是您的坐标也使用的任何单位.如果坐标以英尺为单位，则距离以英尺为单位；否则，距离以英尺为单位.如果距离以纬度/经度为单位，则需要以度为单位表示所需的缓冲距离.

The units would be whatever units your coordinates are also using. If the coordinates are in feet, the distance is expressed in feet; if the distance is in degrees lat/long, you'd need to express the desired buffer distance in degrees.

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