Google Earth Engine（gee）中的Feature

目录

ee.Feature() 

Feature.select()

Feature中的set、setMulti

Feature.transform()

Feature.centroid/simplify/bounds/convexHull/buffer()

Feature.union/intersection/difference/symmetricDifference()

Feature中计算面积:area()、周长:perimeter()

---

ee.Feature() 

var geometry_tianfu= ee.Geometry.Polygon([[[104.06431420192233, 30.65820626544307],
                                          [104.06455023631564, 30.656581911340815],
                                          [104.06714661464206, 30.656581911340815],
                                          [104.06733973369113, 30.658372391028514]]])
              
var properties_tianfu=  {
          "name": "天府广场",
          "location": "成都",
          "system:index": "0"
        }     
        
var feature_tianfu =ee.Feature( geometry_tianfu,properties_tianfu);
print(feature_tianfu)

Map.centerObject(feature_tianfu)
Map.addLayer(feature_tianfu)

Feature.select()

提取出想要的属性，并给属性名改名

var geometry_tianfu= ee.Geometry.Polygon([[[104.06431420192233, 30.65820626544307],
                                          [104.06455023631564, 30.656581911340815],
                                          [104.06714661464206, 30.656581911340815],
                                          [104.06733973369113, 30.658372391028514]]])
              
var properties_tianfu=  {
          "name": "天府广场",
          "location": "成都",
          "system:index": "0"
        }     
        
var feature_tianfu =ee.Feature( geometry_tianfu,properties_tianfu);
print(feature_tianfu)
print(feature_tianfu.select(["name"]))
print(feature_tianfu.select(["name"],["名称"]))

Feature中的set、setMulti

var geometry_tianfu= ee.Geometry.Polygon([[[104.06431420192233, 30.65820626544307],
                                          [104.06455023631564, 30.656581911340815],
                                          [104.06714661464206, 30.656581911340815],
                                          [104.06733973369113, 30.658372391028514]]])
              
var properties_tianfu=  {
          "name": "天府广场",
          "location": "成都",
          "system:index": "0"
        }     
        
var feature_tianfu =ee.Feature( geometry_tianfu,properties_tianfu);
print(feature_tianfu)
print(feature_tianfu.set('location','chengdu'))
print(feature_tianfu.setMulti({'name':'chengdu','location':"tianfuguangchang"}))

Feature.transform()

print("myGeometry",myGeometry)

var feature=ee.Feature(myGeometry)
print("feature",feature)

var feature_transform=feature.transform('EPSG:3857',ee.ErrorMargin(100))
print("feature_transform",feature_transform)

print(ee.Geometry(feature.geometry()).projection())
print(ee.Geometry(feature_transform.geometry()).projection())

Feature.centroid/simplify/bounds/convexHull/buffer()

Feature.union/intersection/difference/symmetricDifference()

var feature1 =ee.Feature(ee.Geometry.Polygon(
            [[[103.43534679370603, 31.17014003162498],
              [102.90800304370603, 30.45777180538538],
              [103.71549816089353, 29.911716302186857],
              [104.48454112964353, 30.329839651564306],
              [104.03410167651853, 31.014908583940628]]]))
var feature2 = ee.Feature(ee.Geometry.Polygon(
            [[[104.44608898120603, 31.04785765490257],
              [103.91325206714353, 30.63281369239727],
              [104.30326671558103, 29.959319376777437],
              [105.34147472339353, 30.044947475833734]]]));
              

Map.centerObject(feature1)
Map.addLayer(feature1,{color:"00ffff"},"feature1")
Map.addLayer(feature2,{color:"32CD32"},"feature2")


Map.addLayer(feature1.union((feature2)),{},"union")
Map.addLayer(feature1.intersection((feature2)),{},"intersection")
Map.addLayer(feature1.difference((feature2)),{},"difference")
Map.addLayer(feature1.symmetricDifference((feature2)),{},"symmetricDifference")

Feature中计算面积:area()、周长:perimeter()

• area()：面积函数
• perimeter()：周长函数

print(sichuan)
print(sichuan.first())
print("面积",ee.Feature(sichuan.first()).area())
print("周长",ee.Feature(sichuan.first()).perimeter())