简介

地形（Terrain）提供描述地形坡度、坡向、山体阴影等特征的算法集合。

aspect

根据DEM数据进行坡向计算，获取坡向影像。

函数	返回值
aspect(self)	Image

示例

geometry = pie.Geometry.Polygon([[
    [
        120.14843750000063,
        41.78937765652833
    ],
    [
        120.78564453125199,
        41.97750297114209
    ],
    [
        120.77465820312324,
        41.53494144776468
    ],
    [
        120.33520507812159,
        41.56782841155561
    ],
    [
        120.14843750000063,
        41.78937765652833
    ]
    ]], None)
# 计算地形坡向
id1 = "LC08/01/T1/LC08_121031_20170117"
imageB = pie.Image(id1).select('B1')
ter = pie.Terrain(imageB)
print('aspect:',ter.aspect().getInfo())

hillShade

通过数字高程模型计算山体阴影。

函数	返回值
hillShade(input,altitude,azimuth,zScaleFactor)	Image

参数	类型	说明
input	Image	输入高程影像，单位为米
altitude	Float, default: 45	太阳高度角，单位为度
azimuth	Float, default: 315	太阳方位角，单位为度
zScaleFactor	Z因子, default: 1	垂直方向因子，当垂直（或高程）方向与水平方向坐标单位不同时，可以使用z因子调整垂直（或高程）方向的测量单位

示例

Map = pie.Map()
image_dem = pie.ImageCollection('DEM/ASTGTM_003').first().select("dem")
imageShade = pie.Terrain.hillShade(image_dem,45,315,8)
visParam = {
    'opacity':0.5,
    'classify':'-11000,-8000,-7000,-6000,-5000,-4000,-3000,-2000,-1000,-500,-200,-100,-50,0,50,100,250,500,750,1000,1250,1500,1750,2000,2500,3000,3500,4000,4500,5000,5500,6000,8800',
    'palette':'145999,1b76cc,1f86e6,26aaea,36b6eb,4dc0eb,60cfeb,77daef,b0dfef,d1e5ee,dce6f0,e1e7f2,dee6f1,43c370,44b772,52c88e,' +'6fc993,7ecb97,acd2ad,d4c97a,d0bc59,d3b146,c78f3c,c3812d,c5762b,b95322,ae4621,ba6e78,bc8fa9,c7aac6,dbcdde,fffcff'}
image_out = pie.Image(255).subtract(imageShade).abs()
Map.addLayer(image_dem,visParam,'dem')
Map

slope

根据DEM数据进行坡度计算，获取以度为单位的坡度影像。

函数	返回值
split(self)	Image

示例

geometry = pie.Geometry.Polygon([[
    [
        120.14843750000063,
        41.78937765652833
    ],
    [
        120.78564453125199,
        41.97750297114209
    ],
    [
        120.77465820312324,
        41.53494144776468
    ],
    [
        120.33520507812159,
        41.56782841155561
    ],
    [
        120.14843750000063,
        41.78937765652833
    ]
    ]], None)
# 计算地形坡度
id1 = "LC08/01/T1/LC08_121031_20170117"
imageB = pie.Image(id1).select('B1')
ter = pie.Terrain(imageB)
print('slope:',ter.slope().getInfo())