第2节 根据DEM提取河网

1. 利用 arcgis 的空间分析模块生成水网，然后人工在进行修饰

• 需要修改的参数：

• (1) 一个是DEM的文件名称（此脚本需要把 DEM 加载到视图中）

• (2) 一个是累积流量，一般根据经验值或者测量的数据，即就是 streamrs 中VALUE 参数值得设定，值越大，得到的河网越密，反之则稀疏

# -*- coding: utf-8 -*-
# ---------------------------------------------------------------------------
# hydro.py
# Created on: 2016-12-06
# Usage: hydrology analysis
# Description: result include watershed, basin, stream(with order)
# ---------------------------------------------------------------------------

# Import arcpy module
import arcpy
arcpy.env.overwriteOutput = True
from arcpy import env
from arcpy.sa import *

# Set workspace
arcpy.env.workspace = "G:\JLRiver\JLRiverDem\dem"

# Input DEM ratser file
DEM = "thailandl"

# Check SRS
sr = arcpy.Describe(DEM).spatialReference
print "Spatial Reference System:" + sr.name
# Check out any necessary licenses
print "Spatial Analyst Extension Available:"
print arcpy.CheckOutExtension("spatial")


# Process
fill = Fill(DEM)
flowdir = FlowDirection(fill, "NORMAL")
flowacc = FlowAccumulation(flowdir, "", "FLOAT")
streamrs = SetNull(flowacc, 1, "VALUE <= 900") # flowacc <=900 -> null, 900+ -> 1
streamlink = StreamLink(streamrs2, flowdir)

watershedrs = Watershed(flowdir, streamlink, "VALUE")
arcpy.RasterToPolygon_conversion(watershedrs, "watershed", "NO_SIMPLIFY", "VALUE") # watershed polygon saved

streamorder = StreamOrder(streamrs, flowdir, "STRAHLER")
# Attention! this one goes wrong: stream = StreamToFeature(streamorder, flowdir, "SIMPLIFY")
StreamToFeature(streamorder, flowdir, "stream", "SIMPLIFY") # stream polyline saved

basinrs = Basin(flowdir)
arcpy.RasterToPolygon_conversion(basinrs, "basin", "NO_SIMPLIFY","VALUE") # basin polygon saved

print "All done, Check 'stream, basin, watershed' in Current Workspace."