Rails 3 GPS坐标的浮点数或小数点

问题描述

我需要将GPS坐标存储在数据库中。我听说花车不如小数准确。真的吗？如果是这样，有什么理由是曾经使用浮动？

解决方案

如果你想要更精确的GPS坐标，然后是小数是要走的路。你可以使用如下的迁移来创建它们：

  create_tablemodelsdo | t | 
 t.decimallatitude，：precision => 15，：scale => 10，：default => 0.0 
 t.decimallongitude，：precision => 15，：scale => 10，：default => 0.0 
 end 
  

人们使用浮动的原因是它们通常足够精确，案件和使用较少的空间来存储。

I need to store GPS coordinates in a database. I've heard that floats are less accurate than decimals. Is that true? If so, what reason is there to ever use floats?

解决方案

If you want more accurate GPS coordinates, then yes decimals are the way to go. You can create them with a migration like:

create_table "models" do |t|
  t.decimal  "latitude", :precision => 15, :scale => 10, :default => 0.0
  t.decimal  "longitude", :precision => 15, :scale => 10, :default => 0.0
end

The reason people use floats is that they are usually precise enough for most use cases and use less space to store.

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