认识 Python工具箱

python 工具箱 (.pyt) 是一个简单的文本文件，可以在任何文本编辑器中或者任何 Python IDE 中创建、查看和编辑。要确保 ArcGIS 正确识别 Python 工具箱，工具箱类的名称必须是
Toolbox。在 Toolbox 类的
__init__ 方法中定义工具箱的属性，这些属性包括 alias、label 和 description，我们可以按照
帮助文档 中的模板构建 Python 工具箱模板。

如下代码中创建了包含一个工具（名为 Tool）的 Python 工具箱：

import arcpy


class Toolbox(object):
    def __init__(self):
        """Define the toolbox (the name of the toolbox is the name of the
        .pyt file)."""
        self.label = "Toolbox"
        self.alias = ""

        # List of tool classes associated with this toolbox
        self.tools = [Tool]


class Tool(object):
    def __init__(self):
        """Define the tool (tool name is the name of the class)."""
        self.label = "Tool"
        self.description = ""
        self.canRunInBackground = False

    def getParameterInfo(self):
        """Define parameter definitions"""
        params = None
        return params

    def isLicensed(self):
        """Set whether tool is licensed to execute."""
        return True

    def updateParameters(self, parameters):
        """Modify the values and properties of parameters before internal
        validation is performed.  This method is called whenever a parameter
        has been changed."""
        return

    def updateMessages(self, parameters):
        """Modify the messages created by internal validation for each tool
        parameter.  This method is called after internal validation."""
        return

    def execute(self, parameters, messages):
        """The source code of the tool."""
        return

动手做做

下面我就依据这个模板，写一个简单的脚本工具箱。需求是批量裁剪，我希望我只提供一个文件夹或者数据库等这样的工作空间和一个裁剪区域面，就可以批量完成工作空间内全部数据的裁剪工作，并且无视栅格还是矢量，一并裁剪。

Let the scripting begin ……

1 创建工具箱

'''
Source Name:   ClipWorkspace.pyt
Author:        Kikita
Description:   Python tool to clip spatial data in the same workspace by batch.
'''

import arcpy

# The class name must be "Toolbox" ...
class Toolbox(object):
    def __init__(self):

        self.label = "Clip Workspace Toolbox"
        self.alias = ""

        # List of tool classes associated with this toolbox
        self.tools = [ClipWorkspace]


class ClipWorkspace(object):
    ……

2 定义工具

class ClipWorkspace(object):

    def __init__(self):
        self.label = "Clip Workspace"
        self.description = "clip spatial data in the same workspace by batch."
        self.canRunInBackground = True

有了工具的构造函数，我们继续看如何给工具定义参数。在 Python 工具箱 (.pyt) 中，可在工具类的 getParameterInfo 方法中创建
Parameter 对象，并设置对象的属性来定义工具参数。Parameter的属性中datatype

包含的类型可以在帮助文档中查询，点这里。

此示例中的参数就是输入工作空间（inWorkspace）、裁剪区域面（ClipArea）、输出工作空间（outWorkspace）。

    def getParameterInfo(self):

        # Parameter Definitions
        # First parameter - Input Workspace
        param0 = arcpy.Parameter(
            displayName="Input Workspace",
            name="inWorkspace",
            datatype="DEWorkspace",
            parameterType="Required",
            direction="Input")

        # Second parameter - Clip Area
        param1 = arcpy.Parameter(
            displayName="Clip Area",
            name="CLipArea",
            datatype="DEFeatureClass",
            parameterType="Required",
            direction="Input")

        # Third parameter - Output Workspace
        param2 = arcpy.Parameter(
            displayName="Output Workspace",
            name="outWorkspace",
            datatype="DEWorkspace",
            parameterType="Required",
            direction="Input")

        params = [param0,param1,param2]
        return params   

• 1

PS : 在代码中，如果仔细看，或许你会疑惑，为何输出工作空间的方向是 input ，而不是 output？ 因为工具最终输出的为 Feature Class 或 Raster，输出工作空间也是作为输入参数传入工具使用的。如果不关心，也可以不在意这些细节…… 继续向下了解工具的构建过程。

下面就是工具的具体执行部分了，当然里面还加了些辅助了解工具执行状态的消息：

    def execute(self, parameters, messages):

        """The source code of the tool."""

        # Get tool parameters
        inWorkspace = parameters[0].valueAsText
        arcpy.AddMessage("###Input Workspace is {0}".format(inWorkspace))

        ClipArea = parameters[1].valueAsText
        arcpy.AddMessage("###Clip Area is {0}".format(ClipArea))

        outWorkspace =  parameters[2].valueAsText
        arcpy.AddMessage("###Out Workspace is {0}".format(outWorkspace))


        # Clip Feature by Batch
        arcpy.env.workspace = inWorkspace

        # Clip Vector
        FeatureClasses = arcpy.ListFeatureClasses()
        arcpy.AddMessage("Input Workspace contains {0}".format(FeatureClasses))
        for fc in FeatureClasses:
            arcpy.AddMessage(">> Clipping  {0}".format(fc))
            arcpy.Clip_analysis(fc,ClipArea, os.path.join(outWorkspace,fc))
            arcpy.AddMessage("{0} has been clipped.".format(os.path.join(outWorkspace,fc)))

        # Clip Raster
        Rasters = arcpy.ListRasters()
        arcpy.AddMessage("Input Workspace contains {0}".format(Rasters))
        for Raster in Rasters:
            arcpy.AddMessage(">> Clipping  {0}".format(Raster))
            arcpy.Clip_management(in_raster = Raster,
                                  rectangle = "",
                                  out_raster = os.path.join(outWorkspace,Raster),
                                  in_template_dataset = ClipArea,
                                  nodata_value = "",
                                  clipping_geometry = "ClippingGeometry",
                                  maintain_clipping_extent = "NO_MAINTAIN_EXTENT")
            arcpy.AddMessage("{0} has been clipped.".format(os.path.join(outWorkspace,Raster)))

        return

到这里，工具的核心部分已经完成，执行下试试。

OK，应该是预期的结果：

3 完善