方法一：使用计算几何，计算字段的长度
方法二：使用python2的代码计算
输入以下代码后回车：
import arcpytry:# 获取当前地图中的所有图层mxd = arcpy.mapping.MapDocument("CURRENT")layers = arcpy.mapping.ListLayers(mxd)# 查找第一个线图层target_layer = Nonefor layer in layers:if layer.isFeatureLayer:desc = arcpy.Describe(layer)if desc.shapeType == "Polyline":target_layer = layerbreakif target_layer is None:print "No line layer found"exit()print "Layer: " + target_layer.name# 检查是否有选中要素desc = arcpy.Describe(target_layer)if not desc.FIDSet:print "No selection, calculating all features"# 定义投影坐标系projected_cs = arcpy.SpatialReference(32650) # UTM Zone 50N# 计算长度total_length = 0count = 0with arcpy.da.SearchCursor(target_layer, ["SHAPE@"]) as cursor:for row in cursor:if row[0]:projected_geom = row[0].projectAs(projected_cs)length = projected_geom.lengthtotal_length += lengthcount += 1print "Features: " + str(count)# 格式化输出if total_length >= 1000:length_km = total_length / 1000.0print "Length: {:.2f} km".format(length_km)print "Length: {:.2f} m".format(total_length)else:print "Length: {:.2f} m".format(total_length)except Exception as e:print "Error: " + str(e)
