arcpy给字段计算bsm
时间: 2024-10-22 21:20:19 浏览: 34
ArcPy是一个Python模块,用于访问Esri地理信息系统(GIS)产品的数据和功能,如ArcMap、ArcSDE等。当你想要通过Python脚本在ArcGIS环境中对字段进行数学运算,比如计算某个字段的平均值(Base Statistics,简称BSM),你可以使用arcpy.da模块中的函数。
例如,如果你想计算表(Table)字段`Field_A`的算术平均值(Average),可以按照以下步骤操作:
```python
import arcpy
# 假设你的表名为"YourTable",需要计算的字段为"Field_A"
table = r"C:\path\to\your\file.gdb\YourTable"
# 使用arcpy的GetCount_management获取记录数
total_records = int(arcpy.GetCount_management(table).getOutput(0))
# 如果字段存在,则使用arcpy.da.TableStatistics方法计算平均值
if arcpy.ListFields(table, "Field_A"):
with arcpy.da.SearchCursor(table, ["Field_A"]) as cursor:
field_values = [row[0] for row in cursor]
avg_field_A = sum(field_values) / total_records
print(f"Field_A的平均值是: {avg_field_A}")
else:
print("Field_A不存在于表中.")
# 计算并存储结果到新字段(假设名为"Field_BSM")
arcpy.AddField_management(table, "Field_BSM", "DOUBLE")
arcpy.CalculateField_management(table, "Field_BSM", "!Field_A! / !" + str(total_records), "PYTHON_9.3", "#")
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