球面坐標系
![球面坐標變換](/img/b/848/wZwpmL1YDNwYzMwMzMzIDN0UTMyITNykTO0EDMwAjMwUzLzMzL4QzLt92YucmbvRWdo5Cd0FmLwE2LvoDc0RHa.jpg)
![球面坐標變換](/img/f/fdb/wZwpmL4YTM0YTO5ITOwMzM1UTM1QDN5MjM5ADMwAjMwUzLykzL1MzLt92YucmbvRWdo5Cd0FmLxE2LvoDc0RHa.jpg)
![球面坐標變換](/img/b/848/wZwpmL1YDNwYzMwMzMzIDN0UTMyITNykTO0EDMwAjMwUzLzMzL4QzLt92YucmbvRWdo5Cd0FmLwE2LvoDc0RHa.jpg)
![球面坐標變換](/img/5/c01/wZwpmL3IzM0ADMxcTOwcTN1UTM1QDN5MjM5ADMwAjMwUzL3kzLxgzLt92YucmbvRWdo5Cd0FmLxE2LvoDc0RHa.jpg)
定義. 設是中一點,在球面坐標系中的三個坐標變數是,其定義為
•徑向距離是從原點到點P的歐幾里得距離。
•傾角(或極角) θ是天頂方向和線段OP之間的夾角。
•方位(或方位角) φ是從方位參考方向到參照平面上線段OP的正交投影的有符號角度。
見右圖1。
![圖1](/img/e/783/wZwpmLzYTO1QTM0QTOwcTN1UTM1QDN5MjM5ADMwAjMwUzL0kzLwYzLt92YucmbvRWdo5Cd0FmLyE2LvoDc0RHa.jpg)
![球面坐標變換](/img/5/c01/wZwpmL3IzM0ADMxcTOwcTN1UTM1QDN5MjM5ADMwAjMwUzL3kzLxgzLt92YucmbvRWdo5Cd0FmLxE2LvoDc0RHa.jpg)
![球面坐標變換](/img/5/112/wZwpmL4UDN3ETOwkDO0ATN0UTMyITNykTO0EDMwAjMwUzL5gzL2AzLt92YucmbvRWdo5Cd0FmLzE2LvoDc0RHa.jpg)
與極坐標類似,球面坐標系相同的同一點,具有無限多個等效坐標,,你可以在不改變角度的情況下, 增加或減去任意數量倍的,從而不改變角點。在許多情況下,允許負徑向距離也很方便,,該慣例是(− r, θ, φ)等效於( r, θ+ 180 °, φ)為任意r,θ和φ。此外,( r,− θ, φ)等效於( r, θ, φ+ 180 °)。
如果需要為每個點定義一組唯一的球面坐標, 則必須限制它們的範圍。一個共同的選擇是:
![球面坐標變換](/img/d/05f/wZwpmLxcDM2UDN3ITOwcTN1UTM1QDN5MjM5ADMwAjMwUzLykzLyYzLt92YucmbvRWdo5Cd0FmL0E2LvoDc0RHa.jpg)
球面坐標變換
![球面坐標變換](/img/f/13e/wZwpmL2MDOzMTN5UTMzEzM1UTM1QDN5MjM5ADMwAjMwUzL1EzLwAzLt92YucmbvRWdo5Cd0FmLxE2LvoDc0RHa.jpg)
![球面坐標變換](/img/5/c01/wZwpmL3IzM0ADMxcTOwcTN1UTM1QDN5MjM5ADMwAjMwUzL3kzLxgzLt92YucmbvRWdo5Cd0FmLxE2LvoDc0RHa.jpg)
球面坐標系是三大常用的坐標系之一,其它二個常用的坐標系是標準的歐氏坐標系、柱面坐標系。球面坐標變換公式描述了空間中一點P在歐氏坐標系下的坐標與球面坐標系下的坐標之間的變換關係。該變換關係如下述公式給出 :
![球面坐標變換](/img/f/13e/wZwpmL2MDOzMTN5UTMzEzM1UTM1QDN5MjM5ADMwAjMwUzL1EzLwAzLt92YucmbvRWdo5Cd0FmLxE2LvoDc0RHa.jpg)
![球面坐標變換](/img/5/c01/wZwpmL3IzM0ADMxcTOwcTN1UTM1QDN5MjM5ADMwAjMwUzL3kzLxgzLt92YucmbvRWdo5Cd0FmLxE2LvoDc0RHa.jpg)
![球面坐標變換](/img/0/e4e/wZwpmLxUzM0QTN5IDOwcTN1UTM1QDN5MjM5ADMwAjMwUzLygzL3UzLt92YucmbvRWdo5Cd0FmLwE2LvoDc0RHa.jpg)
或者,將表達成的形式:
![球面坐標變換](/img/9/51c/wZwpmL0cDNyMjMwYTOwcTN1UTM1QDN5MjM5ADMwAjMwUzL2kzL3gzLt92YucmbvRWdo5Cd0FmLxE2LvoDc0RHa.jpg)
體積元
在許多套用中,球面坐標系具有其它坐標系不具有的優點。了解在球面坐標系的面積元,體積元是對我們有幫助的。
長度元:
![球面坐標變換](/img/4/10c/wZwpmLzATO3ETOwMTOwcTN1UTM1QDN5MjM5ADMwAjMwUzLzkzLxAzLt92YucmbvRWdo5Cd0FmLxE2LvoDc0RHa.jpg)
其中
![球面坐標變換](/img/b/1f6/wZwpmL3QTO4AzN1IDMxcTN1UTM1QDN5MjM5ADMwAjMwUzLyAzL0QzLt92YucmbvRWdo5Cd0FmLyE2LvoDc0RHa.jpg)
面積元:
![球面坐標變換](/img/5/75e/wZwpmL1QjMyUTOyUDOwcTN1UTM1QDN5MjM5ADMwAjMwUzL1gzL4EzLt92YucmbvRWdo5Cd0FmLyE2LvoDc0RHa.jpg)
![球面坐標變換](/img/a/36f/wZwpmLzYDOxgDNzUDMxcTN1UTM1QDN5MjM5ADMwAjMwUzL1AzL2AzLt92YucmbvRWdo5Cd0FmLyE2LvoDc0RHa.jpg)
![球面坐標變換](/img/9/15e/wZwpmL0EDNwIDM1ATMxcTN1UTM1QDN5MjM5ADMwAjMwUzLwEzLzYzLt92YucmbvRWdo5Cd0FmLxE2LvoDc0RHa.jpg)
體積元:
![球面坐標變換](/img/4/ab7/wZwpmLyYzN1UjNwATMxcTN1UTM1QDN5MjM5ADMwAjMwUzLwEzL2AzLt92YucmbvRWdo5Cd0FmL0E2LvoDc0RHa.jpg)
梯度、散度、旋度以及Laplace運算元在球面坐標系下的由下述公式給出 :
![球面坐標變換](/img/e/bb3/wZwpmL3MzN1ATM0UDOwcTN1UTM1QDN5MjM5ADMwAjMwUzL1gzL3YzLt92YucmbvRWdo5Cd0FmLzE2LvoDc0RHa.jpg)