LinearUnitConversionFactor

摘要

返回将距离测量值转换为其他线性单位的因子。

说明

该函数支持的线性单位与从地理处理线性单位参数数据类型返回的单位相同，例外情况如下：

• Unknown - 只能转换已知单位。
• Decimal Degrees - 十进制度在球体上测量并且与其他单位的转换因子不一致。

了解有关地理处理测量单位的详细信息

语法

LinearUnitConversionFactor (from_unit, to_unit)

参数	说明	数据类型
from_unit	The original or source linear unit. Kilometers—Kilometers Meters—Meters Decimeters—Decimeters Millimeters—Millimeters Centimeters—Centimeters NauticalMilesInt—International nautical miles MilesInt—Statute miles YardsInt—International yards FeetInt—International feet InchesInt—International inches NauticalMilesUS—US survey nautical miles MilesUS—US survey miles YardsUS—US survey yards FeetUS—US survey feet InchesUS—US survey inches Points—Points	String
to_unit	The target or destination linear unit. Kilometers—Kilometers Meters—Meters Decimeters—Decimeters Millimeters—Millimeters Centimeters—Centimeters NauticalMilesInt—International nautical miles MilesInt—Statute miles YardsInt—International yards FeetInt—International feet InchesInt—International inches NauticalMilesUS—US survey nautical miles MilesUS—US survey miles YardsUS—US survey yards FeetUS—US survey feet InchesUS—US survey inches Points—Points	String

返回值

数据类型	说明
Double	用于在两个线性单位之间转换值的转换因子。

代码示例

LinearUnitConversionFactor 示例 1

从国际英里转换为千米的简单用例。

import arcpy

# Convert 620.5 MilesInt to Kilometers
620.5 * arcpy.LinearUnitConversionFactor(from_unit="MilesInt", to_unit="Kilometers")

print(area)  # This will print a value of 998.597952

LinearUnitConversionFactor 示例 2

在脚本工具中，将指定值转换为米以进行处理。

import arcpy
import locale
import sys

dist = arcpy.GetParameter(n)  # Update n to the parameter index
dist_value, dist_unit = dist.split(" ")  # For example, "10 Kilometers"

# Convert the distance into "Meters" as needed later in this script
try:
    conv_factor = arcpy.LinearUnitConversionFactor(dist_unit, "Meters")
except ValueError as e:
    # If fails, the likely distance unit is "Unknown" or "Decimal Degrees".
    # Add code to either deal with it or produce an appropriate error as shown below.
    arcpy.AddError('Invalid linear unit type.')
    sys.exit()

# Apply the conv_factor to the supplied value
# locale.atof is required for locales that don't use a period as the separator
dist_m = locale.atof(dist_value) * conv_factor