Building Tools with Python. Evan Caldwell

Transcription

1 Building Tools with Python Evan Caldwell

2 A quick note on help resources.arcgis.com

3 And for general help with Python Documentation Tutorials (free as in beer) Communities ons/tagged/python

4 Tool Components and what we re covering in this workshop Parameter Definition Briefly covered Tool Validation The emphasis of this workshop Execution Not covered

5 Parameter Definition

6 Parameter Definition Requirements Type Required Optional Derived Name e.g. startdate, enddate, inputfc, etc Must be unique! Data Type string, integer, file, boolean, feature class, etc Direction Input Output

7 Parameter Filters Filter Value List Range Feature Class File Field Workspace Description A list of string or numeric values. Used with String, Long, Double, and Boolean parameter data types. A minimum and maximum value. Used with Long and Double data types. A list of allowable feature class types: Point, Multipoint, Polyline, Polygon, MultiPatch, Sphere, Annotation, Dimension. More than one value can be supplied to the filter. A list of file suffixes. Example: "txt; e00; ditamap". A list of allowable field types: Short, Long, Single, Double, Text, Date, OID, Geometry, Blob, Raster, GUID, GlobalID, XML. More than one value can be supplied to the filter. A list of allowable workspace types: File System, Local Database, Remote Database. More than one value can be supplied.

8 Normal Toolbox Script What does it look like?

9 Normal Toolbox Script How does Python read it? # Get script parameters. dbpath = arcpy.getparameterastext(0) dbname = os.path.split(dbpath)[1] startdate = sys.argv[2] enddate = sys.argv[3] createtracks = arcpy.getparameterastext(3) pointspersegment = int(sys.argv[8])

10 Normal Toolbox Script How does Python read it? getparameterastext 0 based Sys.argv[x] 0 based, but starts at 1 getparameterastext(x) sys.argv[x]

11 Python Toolboxes New at 10.1

12 Python Toolbox Components class Toolbox(object): def init class script1(object): class script2(object): class script3(object): def init def getparameterinfo(self):

13 Python Toolbox Script What does it look like?

14 Python Toolbox Script How does Python read it? def getparameterinfo(self): """Define parameter definitions""" # Param0. param0 = arcpy.parameter() param0.displayname = 'Sqlite Database' param0.name = 'sqlite_database' param0.datatype = 'File' param0.value = r'e:\demos\gpstracker\androidhistory.sqlite' param0.parametertype = 'Required' param0.direction = 'Input'... params = [param0, param1, param2, param3, param4, param5, param6, param7] return params 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.""" startdate = parameters[1].value enddate = parameters[2].value

15 Tool Validation

16 Tool Validation Why bother? Save time - e.g. running intersect on non-overlapping features Avoid errors - e.g. trying to use a point FC when a polygon is expected Provide the user with information or assistance - e.g. populate a list with acceptable inputs

17 Running a script without Tool Validation Ever seen this?

18 Running a script with Tool Validation Much more informative

19 Tool Validation Access this dialog by right clicking a script in the ArcToolbox window

20 Tool Validation Class methods Method init Import libraries Uses initializeparameters Set initial values updateparameters Check parameters Enable/disable parameters Populate parameters based on another Do stuff when something changes Add/update warnings and errors updatemessages

21 init Example def init (self): """Setup arcpy and the list of tool parameters.""" import arcpy import time import sqlite3 self.params = arcpy.getparameterinfo()

22 initializeparameters Example def initializeparameters(self): """Refine the properties of a tool's parameters. This method is called when the tool is opened.""" # Set default values. self.params[0].value = r'c:\gis\projects_internal\gpstracker\androidhistory.sqlite' self.params[1].value = time.strftime('%y-%m-%d', time.localtime()) + ' 16:05:00' self.params[2].value = time.strftime('%y-%m-%d', time.localtime()) + ' 20:05:00' self.params[3].enabled = True self.params[7].enabled = False self.params[7].value = 5 return

23 def updateparameters(self): """Modify the values and properties of parameters before internal validation is performed. This method is called whenever a parameter has been changed.""" startdate = self.params[1].value enddate = self.params[2].value # Format the user entered dates as seconds and multiply by 1000 to get milliseconds. T1 = time.mktime(time.strptime(str(startdate), '%Y-%m-%d %H:%M:%S')) * 1000 T2 = time.mktime(time.strptime(str(enddate), '%Y-%m-%d %H:%M:%S')) * 1000 conn = sqlite3.connect(str(self.params[0].value)) c = conn.cursor() # Create the selection statement using the user-specified time extent. statstatement = 'SELECT COUNT (*) as count, min(timestamp) as min, max(timestamp) as ma c.execute(statstatement) for row in c: count = row[0] if not count == 0: mintime = time.strftime("%m/%d/%y %H:%M:%S %p", time.localtime(row[1]/1000)) maxtime = time.strftime("%m/%d/%y %H:%M:%S %p", time.localtime(row[2]/1000)) self.params[6].value = str(count) + ' points found from ' + mintime + ' to ' + maxti else: self.params[6].value = '0 points found from ' + str(startdate) + ' to ' + str(enddat self.params[6].enabled = False updateparameters Example

24 updatemessages Example def updatemessages(self): """Modify the messages created by internal validation for each tool parameter. This method is called after internal validation.""" if self.params[6].value[0] == '0': self.params[6].seterrormessage('there are 0 points in the database for the selected da return

25 Examples

26 Questions?

27 Upcoming Events ( March 8 April 12 MeetUp at Esri (Vienna, VA) MeetUp in DC area (location TBD) Mar Esri Partner Conference (Palm Springs, CA) Mar Esri Developer Summit (Palm Springs, CA) July Esri Homeland Security Summit (San Diego, CA) July Esri International User Conference (San Diego, CA)

28 Friday Closing Session and Hosted Lunch Join conference attendees for lunch and closing session 11:30 am 1:30 pm Ballrooms A-C, Third Level Closing Speaker Chris Smith, United States Department of Agriculture Wrap-up and request for feedback with Jack Dangermond of closing session...

29 Thank You Please complete session evaluation form