利用两期地表DEM数据计算工程土方量需要准许以下数据：
当前地图有3个图层，两个栅格图层和一个矢量图层
两个栅格图层：beforeDem为工程施工前的地表DEM模型
afterDem为工程施工后的地表DEM模型
一个矢量图层：pFeatureLayer
第一步生成掩膜：面转栅格 conversion.PolygonToRaster 生产名称为“poly”的栅格数据。
OID为pFeatureLayer的字段
pFeatureLayer = PMap.FindLayers(ComboBox4.Text).FirstOrDefault
If pFeatureLayer IsNot Nothing Then
GoTo qqww
Dim maskRaster As String = Path.Combine(Project.Current.DefaultGeodatabasePath, $"poly")
va = Geoprocessing.MakeValueArray(pFeatureLayer, "OID", maskRaster) ' 直接传递环境参数列表
Dim result = Await Geoprocessing.ExecuteToolAsync("PolygonToRaster_conversion", va)
If result.IsFailed Then
Throw New Exception($"掩膜生成失败: {String.Join(vbCrLf, result.ErrorMessages)}")
End If第二步生成掩膜：按掩膜提取分别生成两个栅格图层
before_clipped：为工程施工前的地表DEM的提取模型
after_clipped ：为工程施工后的地表DEM的提取模型
Dim outputName As String
Dim inputRaster As String
Dim outputPath As String
Dim envSettings = New List(Of KeyValuePair(Of String, Object))
For i = 1 To 2
If i = 1 Then inputRaster = beforeDem : outputName = "before_clipped"
If i = 2 Then inputRaster = afterDem : outputName = "after_clipped"
'直接传递环境参数列表
envSettings = New List(Of KeyValuePair(Of String, Object)) From {New KeyValuePair(Of String, Object)("cellSize", "MAXOF"), New KeyValuePair(Of String, Object)("template", inputRaster)}
outputPath = Path.Combine(Project.Current.DefaultGeodatabasePath, outputName)
Dim extractParams = Geoprocessing.MakeValueArray(inputRaster, maskRaster, outputPath, "INSIDE")
result = Await Geoprocessing.ExecuteToolAsync("ExtractByMask", extractParams) 'ExtractByMask
If result.IsFailed Then
MsgBox(inputRaster & "栅格按掩膜提取失败")
End If
Next第三步CutFill分析：执行CutFill分析，分析结果生成分析栅格数据CutFill_Result
'1. 裁剪DEM到指定范围
Dim clippedBefore = Path.Combine(Project.Current.DefaultGeodatabasePath, "before_clipped")
Dim clippedAfter = Path.Combine(Project.Current.DefaultGeodatabasePath, "after_clipped")
'2. 执行CutFill分析
outputName = "CutFill_Result"
outputPath = System.IO.Path.Combine(Project.Current.DefaultGeodatabasePath, outputName)
Dim parameters = Geoprocessing.MakeValueArray(clippedBefore, clippedAfter, outputPath, "METER")
result = Await Geoprocessing.ExecuteToolAsync("CutFill", parameters)
If result.IsFailed Then
Throw New Exception($"CutFill分析失败: {String.Join(vbCrLf, result.ErrorMessages)}")
End If第四步分析成果按属性提取：ExtractByAttributes，提取的数据仍然为栅格数据
属性提取Where 子句使用 SQL 查询
"VOLUME < 0" 填方
"VOLUME > 0" 挖方
"VOLUME = 0" 未变化
输出栅格的属性表用于确定显示方式，并且分别将正体积和负体积视为挖出材料的位置（已移除）和填充材料的位置（已添加）。
' 计算挖方量
Dim cutParams = Geoprocessing.MakeValueArray(cutFillRasterPath, "VOLUME > 0", GeodaPath & "\WFMJ") '按属性提取
gpResult = Await Geoprocessing.ExecuteToolAsync("ExtractByAttributes", cutParams)
If gpResult.IsFailed Then
MsgBox("挖方区域提取失败.")
End If
' 计算填方量
Dim fillParams = Geoprocessing.MakeValueArray(cutFillRasterPath, "VOLUME < 0", GeodaPath & "\" & "TFMJ") '按属性提取
gpResult = Await Geoprocessing.ExecuteToolAsync("ExtractByAttributes", fillParams)
If gpResult.IsFailed Then
MsgBox("填方区域提取失败.")
End If
' 计算未变化方量
Dim wbhParams = Geoprocessing.MakeValueArray(GeodaPath & "\" & cutFillRasterPath, "VOLUME = 0", GeodaPath & "\" & "WBHMJ")
gpResult = Await Geoprocessing.ExecuteToolAsync("ExtractByAttributes_management", wbhParams)
If gpResult.IsFailed Then
MsgBox("未变化区域提取失败.")
End If第五步获取栅格数据属性如：
- x 方向上的像元大小—x 方向上的像元大小。
- y 方向上的像元大小—y 方向上的像元大小。
va = Geoprocessing.MakeValueArray("TFMJ", {"CELLSIZEX", "CELLSIZEY"})
gpResult = Await Geoprocessing.ExecuteToolAsync("management.GetRasterProperties", va)
If gpResult.IsFailed Then
MsgBox("栅格数据属性提取失败.")
End If第六步分析栅格数据属性表访问Attributes：
Try
Await QueuedTask.Run(Sub()
' 获取栅格数据集
Dim raster As Raster = rasterLayer.GetRaster()
If raster Is Nothing Then Return
' 正确检查属性表的方法
Dim hasTable As Boolean = False
Try
' 尝试获取属性表
Using table As Table = raster.GetAttributeTable()
hasTable = True
' 获取字段信息
'Dim fields As IReadOnlyList(Of Field) = table.GetDefinition().GetFields()
'Dim fieldNames As String = String.Join(", ", fields.Select(Function(f) f.Name))
'MessageBox.Show($"找到属性表，包含字段: {fieldNames}")
Dim tabrow = table.Search(Nothing, False)
Do While tabrow.MoveNext
'访问属性表
Loop
End Using
Catch ex As Exception When TypeOf ex Is NotSupportedException OrElse
TypeOf ex Is InvalidOperationException
' 捕获不支持属性表的异常
hasTable = False
End Try
If Not hasTable Then
MessageBox.Show("该栅格没有属性表")
End If
End Sub)
Catch ex As Exception
MessageBox.Show($"访问属性表时出错: {ex.Message}")
End Try如果只需要计算方量，第四步、第五步可省略。
运行后，可得：
