GEE python:按照矢量中的几何位置、属性名称和字符串去筛选矢量集合

2024-02-02 13:23:37 浏览数 (1)

要按照矢量中的几何位置去筛选矢量集合，您可以使用空间查询或选择工具。以下是一些示例：

  1. 空间查询工具：许多GIS软件都具有空间查询工具，可帮助您筛选矢量。您可以使用矩形选择工具、圆形选择工具或多边形选择工具选择特定区域的矢量。还可以使用空间查询语言（例如SQL）编写复杂的查询来识别满足特定条件的矢量，例如在指定距离内的点或多边形。
  2. 编写自定义脚本或程序：如果您需要更复杂的筛选，可以编写自定义脚本或程序来筛选矢量。可以使用Python、C 或其他编程语言来构建您的脚本或程序，以根据坐标、属性或其他条件筛选矢量。
  3. 使用地图编辑器：一些GIS软件具有地图编辑器，其中包括选择和编辑矢量的工具。这些工具可帮助您在地图上选择特定区域的矢量，并进行编辑或删除。

无论您选择哪种方法，都应该先确定筛选条件，然后使用适当的工具来筛选矢量集合。

安装地球引擎API和geemap 安装地球引擎的Python API和geemap。geemap Python包是建立在ipyleaflet和folium包之上的，它实现了几个与地球引擎数据层交互的方法，比如Map.addLayer()、Map.setCenter()和Map.centerObject()。下面的脚本检查geemap包是否已经安装。如果没有，它将安装geemap，它会自动安装其依赖项，包括earthengine-api、folium和ipyleaflet。

Installs geemap package

代码语言：javascript复制
import subprocess

try:
    import geemap
except ImportError:
    print('Installing geemap ...')
    subprocess.check_call(["python", '-m', 'pip', 'install', 'geemap'])
代码语言：javascript复制
import ee
import geemap

函数： ee.Filter.contains(leftField, rightValue, rightField, leftValue, maxError) Creates a unary or binary filter that passes if the left geometry contains the right geometry (empty geometries are not contained in anything). 这里需要明确的一点就是这里的Filed就是我们集合中的属性名称，value就是值，这里一般会设定，按照名称或者是属性值的后缀来筛选

Arguments: leftField (String, default: null): A selector for the left operand. Should not be specified if leftValue is specified.

rightValue (Object, default: null): The value of the right operand. Should not be specified if rightField is specified.

rightField (String, default: null): A selector for the right operand. Should not be specified if rightValue is specified.

leftValue (Object, default: null): The value of the left operand. Should not be specified if leftField is specified.

maxError (ErrorMargin, optional): The maximum reprojection error allowed during filter application.

Returns: Filter 代码：

代码语言：javascript复制
# Add Earth Engine dataset
HUC10 = ee.FeatureCollection("USGS/WBD/2017/HUC10")
HUC08 = ee.FeatureCollection('USGS/WBD/2017/HUC08')
roi = HUC08.filter(ee.Filter.eq('name', 'Pipestem'))

Map.centerObject(roi, 10)
Map.addLayer(ee.Image().paint(roi, 0, 3), {}, 'HUC08')

# select polygons intersecting the roi
roi2 = HUC10.filter(ee.Filter.contains(**{'leftValue': roi.geometry(), 'rightField': '.geo'}))
Map.addLayer(ee.Image().paint(roi2, 0, 2), {'palette': 'blue'}, 'HUC10')

roi3 = HUC10.filter(ee.Filter.stringContains(**{'leftField': 'huc10', 'rightValue': '10160002'}))
print(roi3.getInfo())
Map.addLayer(roi3)

结果： {‘type’: ‘FeatureCollection’, ‘columns’: {‘areaacres’: ‘String’, ‘areasqkm’: ‘String’, ‘gnis_id’: ‘String’, ‘huc10’: ‘String’, ‘humod’: ‘String’, ‘hutype’: ‘String’, ‘loaddate’: ‘String’, ‘metasource’: ‘String’, ‘name’: ‘String’, ‘shape_area’: ‘String’, ‘shape_leng’: ‘String’, ‘sourcedata’: ‘String’, ‘sourcefeat’: ‘String’, ‘sourceorig’: ‘String’, ‘states’: ‘String’, ‘system:index’: ‘String’, ‘tnmid’: ‘String’},。。。。

代码：

代码语言：javascript复制
# Add Earth Engine dataset
# Select North Dakota and South Dakota
fc = ee.FeatureCollection('TIGER/2018/States') 
    .filter(ee.Filter.Or(
        ee.Filter.eq('STUSPS', 'ND'),
        ee.Filter.eq('STUSPS', 'SD'),
    ))

image = ee.Image().paint(fc, 0, 2)
# Map.setCenter(-99.844, 37.649, 5)
Map.centerObject(fc, 6)
Map.addLayer(image, {'palette': 'FF0000'}, 'TIGER/2018/States')

ee.Filter.stringContains(leftField, rightValue, rightField, leftValue) Creates a unary or binary filter that passes if the left operand, a string, contains the right operand, also a string.

Arguments: leftField (String, default: null): A selector for the left operand. Should not be specified if leftValue is specified.

rightValue (Object, default: null): The value of the right operand. Should not be specified if rightField is specified.

rightField (String, default: null): A selector for the right operand. Should not be specified if rightValue is specified.

leftValue (Object, default: null): The value of the left operand. Should not be specified if leftField is specified.

Returns: Filter

ee.Filter.stringStartsWith(leftField, rightValue, rightField, leftValue) Creates a unary or binary filter that passes if the left operand, a string, starts with the right operand, also a string.

Arguments: leftField (String, default: null): A selector for the left operand. Should not be specified if leftValue is specified.

rightValue (Object, default: null): The value of the right operand. Should not be specified if rightField is specified.

rightField (String, default: null): A selector for the right operand. Should not be specified if rightValue is specified.

leftValue (Object, default: null): The value of the left operand. Should not be specified if leftField is specified.

Returns: Filter

按照字符串去筛选：

代码语言：javascript复制
# Add Earth Engine dataset
#!/usr/bin/env python
"""Select by strings

"""

# Select states with "A" in its name
fc = ee.FeatureCollection('TIGER/2018/States') 
    .filter(ee.Filter.stringContains('STUSPS', 'A'))

image = ee.Image().paint(fc, 0, 2)
Map.centerObject(fc, 6)
Map.addLayer(image, {'palette': 'FF0000'}, '*A*')



# Select states its name starting with 'A'
fc = ee.FeatureCollection('TIGER/2018/States') 
    .filter(ee.Filter.stringStartsWith('STUSPS', 'A'))

image = ee.Image().paint(fc, 0, 2)
Map.addLayer(image, {'palette': '0000FF'}, 'A*')
工具 集合 脚本 字符串 python

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