1. GEOPROCESARE IN arcgis FOLOSIND PYTHON
UNIVERSITATEA DE VEST DIN TIMISOARA
DEPARTAMENTUL DE GEOGRAFIE
GEOPROCESARE IN arcgis FOLOSIND PYTHON
SUPORT DE CURS SI APLICATII PRACTICE
MASTER: SISTEME INFORMATIONALE GEOGRAFICE
Autor:
OVIDIU CSILLIK

2. Cuprins
INTRODUCERE ARCPY SI PYTHON GEOPROCESSING TOOLS REGULI DE SCRIERE A SCRIPTURILOR NOTIUNI DE BAZA PYTHON EXERCITII DEPANAREA UNUI SCRIPT EXEMPLU DE COD PYTHON
FUNCTII SI PROPRIETATI AVANSATE
FUNCTII DESCRIPTIVE
FUNCTII DE LISTA
FUNCTII CURSOR
FUNCTII DE GEOMETRIE
CREAREA UNEI UNELTE IN ARCTOOLBOX
MAPPING MODULE
MANIPULAREA HARTILOR SI A LAYERELOR

3. CE este arcpy ?!? ArcPy este succesorul modulului arcgisscripting.
Crearea unei baze folositoare si productive pentru:
analiza datelor geografice
conversiilor de date
managementului de date
automatizarii crearii hartilor cu ajutorul Python.
>>> import arcpy
>>> help(arcpy)

4. Arcpy si python Unelte de geoprocesare automate
Cautare in inregistrari, citirea si scrierea valorilor specifice
Manipularea documentelor de harta si layere
Crearea si manipularea geometriei

5. Unde executam codurile python ?!?
Editorul PythonWin
Python IDLE
Fereastra Python din ArcMap

6. Unde executam codurile python ?!?
Field Calculator - ArcMap
Script in Toolbox

7. Geoprocessing tools in ArcGIS
Toolbox Name Alias Analysis Toolbox analysis Cartography Toolbox cartography Conversion Toolbox conversion Coverage Toolbox arc Data Management Toolbox management Geocoding Toolbox geocoding Geostatistical Analyst Tools ga Linear Referencing Toolbox lr Network Analyst Tools na Samples samples Spatial Analyst Toolbox sa Spatial Statistics Toolbox stat 3D Analyst Toolbox 3d

8. Accessing Environment Settings via ArcPy
Environment settings as properties from arcpy.env class:
import arcpy
# setting the environment: object.properties = value
arcpy.env.workspace = "C:\\temp"
arcpy.env.cellSize = 100
# retrieve settings: result = object.properties
variableWorkspace = arcpy.env.workspace
print "the name of the workspace is: " + variableWorkspace
print "cell size is: " + " arcpy.env.cellSize

9. Accessing Tools via ArcPy
Tools can be accessed as functions directly from arcpy
import arcpy
arcpy.env.workspace = "C:\\temp"
# Tool access follows (usually) the following scheme:
# object.Tool (parameter 1, parameter 2, parameter n)
arcpy.Buffer_analysis (InFeature, "c:\\ buff.shp", 100)
input feature class – output - buffer value

10. BINE DE STIUT  Comentariile din interiorul scriptului : #
Numele de variabile nu pot incepe cu o cifra
Case sensitive:
Variables names
Statements
Functions
Geoprocessing function and class names
Not case sensitive:
Pathnames

11. PENTRU CURIOSI  Books Learning Python, (4th Edition) by Mark Lutz
Learn to Program Using Python by Alan Gauld
Programming Python by Mark Lutz
Web sites
Tutorials, documentation, forums
diveintopython.org
Online tutorial book
Learn Python functionality, share sample non-GIS Python scripts

12. Notiuni de baza - Python
Tipuri de date
Variabilele pot stoca valori de diferite tipuri

13. Notiuni de baza - Python
Statements
Indeplinesc o sarcina, dar nu returneaza o valoare
Importarea modulelor in script
Printarea stringurilor in fereastra interactiva

14. Notiuni de baza - Python
Statements
Indeplinesc o sarcina, dar nu returneaza o valoare
Testarea daca o conditie e True sau False
Bucla de cautare intr-o colectie

15. FII PE FAZA !
Gaseste 3 erori in scriptul de mai jos: Gaseste 4 erori in scriptul de mai jos:
if x = 5: print "x is equal to 5" elif x > 5 print "x is greater than 5" else: print "x is not equal to or greater than 5'
# This script buffers the Railroads feature class from the
# SanDiego.gdb geodatabase. The buffer distance is 500 meters
import arcpy
arcpy.env.Workspace = "C:\Student\\PYTH\\Database\\SanDiego.mdb"
inFC = "Railroads"
distance = 500
arcpy.Buffer_analysis(inFC, newBuffFC, distance)

16. FII PE FAZA ! Gaseste 5 erori in scriptul de mai jos:
# This script prints each item in the Python list to the
# Interactive Window.
listFC = ["Airports", "BusStations", "Schools", "Parcels"]
For fc in listFc:
print fc
Print len(lstFc)

17. FII PE FAZA ! Gaseste 3 erori in scriptul de mai jos:
# This script compares the square root of 25 with 6 and
# reports the comparison to the Interactive Window.
Import math
z = 25
y = 6
x = math.sqrt(z)
if x = y:
print "x and y are the same"
elif x > y:
print "x is greater than y"
else
print "x is less than y"

18. Check for syntax errors
Debugging workflow
Check for syntax errors 1
Run with arguments 2
Comment out code 3
Use print statements 4
Use Debugging Toolbar 5

19. Exemplu python
Statement
Variabila
Lista
Bucla FOR

20. PYTHON – FIELD CALCULATOR

21. Functii si proprietati avansate
Proprietati si functii suplimentare, ce nu se gasesc in ArcToolbox

22. Functii si proprietati avansate
Proprietati si functii suplimentare, ce nu se gasesc in ArcToolbox

23. Tipul: integer, string etc.
FUNCTII DESCRIPTIVE
Extrag informatii despre date pentru luarea deciziilor
Shape, Raster, Tabele, Workspace etc.
Linie
Numele campului
Tipul: integer, string etc.

24. rstrip returneaza o copie a stringului din care taie “.shp”
Functii de lista
Obtinerea unei lista cu shape, rastere sau tabele
Adaugarea intr-o geodatabase prin cautarea de .shp intr-o lista
Geodatabase
os.sep = \
# print os.sep
rstrip returneaza o copie a stringului din care taie “.shp”
# gaseste toate .shp

25. Functii cursor Acceseaza o colectie de inregistrari
Citeste si scrie valori in timpul iteratiilor fiecarei inregistrari pe rand

26. FUNCTIA SEARCHCURSOR Row(s) #Set current workspace
Cursor Task
SearchCursor
(parameters)
Row(s)
Reading
#Set current workspace
arcpy.env.workspace = "C:/Student/PYTH/Database/SanDiego.gdb"
#Create cursor on MajorAttractions feature class
curs = arcpy.SearchCursor("MajorAttractions")
# Iterate through the rows in the cursor
# Print the name and Address of each Major Attraction
for row in curs:
print row.Name
print row.Addr
del curs, row

27. Functia updatecursor Row(s) #Set current workspace
Cursor Task
UpdateCursor
(parameters)
Row(s)
Updating
#Set current workspace
arcpy.env.workspace = "C:/Student/PYTH/Database/SanDiego.gdb"
#Create cursor on MajorAttractions feature class
curs = arcpy.UpdateCursor("MajorAttractions",
'"NAME" = \'San Diego Zoo\'')
# Iterate through the rows in the cursor and update the address
for row in curs:
row.Addr = "1900 ZOO PLACE"
cur.updateRow(row)
del curs, row

28. Functia insertcursor #Set current workspace
row
Cursor Task
Insert
InsertCursor
(parameters)
New Row
#Set current workspace
arcpy.env.workspace = "C:/Student/PYTH/Database/SanDiego.gdb"
#Create cursor on MajorAttractions feature class
curs = arcpy.InsertCursor("MajorAttractions")
# Create new row, update fields and insert row.
row = curs.newRow()
row.Name = "BLACK MOUNTAIN PARK"
row.Addr = "12115 BLACK MOUNTAIN RD"
curs.insertRow(row)
del curs, row

29. GEOMETRIA obiectelor
Creare, stergere, mutare sau remodelarea caracteristicilor

30. Script tool Adaugarea unui script ca o unealta in ArcToolbox
Un tool de geoprocesare care executa un script
Full membership in geoprocessing framework
Communicates with ArcGIS applications:
Messages
Environments
Outputs added to map
Etc.

31. Script tool Avantaje Sunt usor de share-uit
Utilizabile si de incepatori (creaza automat casute de dialog)
Pot fi adaugate in Bara de unelte
Inserarea scriptului intr-un Model

32. ArcPy function: GetParameterAsText
Function directly accessible through ArcPy
Used to capture input parameters
This method can only be used with ArcToolbox. Not for use with PythonWin or Command Prompt
Zero based. First argument is at position 0, and each argument thereafter is incremented by one.
import arcpy
# GetParameterAsText function (numbered for each parameter)
arcpy.env.workspace = arcpy.GetParameterAsText(0)
bufFC = arcpy.GetParameterAsText(1)
bufOut = arcpy.GetParameterAsText(2)
bufDist = arcpy.GetParameterAsText(3)
arcpy.Buffer_analysis(bufFC, bufOut, bufDist)

33. Display error message / information messages in ArcGIS
Show error or information messages in the Python Editor:
print statement (only valid in the Python Editor and/or the Python execution window)
and/or
print arcpy.GetMessages() # retrieves ArcGIS/ArcPy specific messages
Show error or information messages in ArcGIS (if a script is executed as a tool):
AddMessage(Message string) # like the print statement
AddWarning(Message string)
AddError(Message string)
Difference in appearance
Display explicit errors in ArcGIS: arcpy.AddMessage(arcpy.GetMessages())

34. Attach a script to a custom tool
General properties
Script location
Parameter properties

35. MAPPING MODULE arcpy.mapping Python scripting library
Open and manipulate map documents (.mxd), layer files (.lyr)
Query and alter contents
Print, export or save the modified document
Automate ArcMap workflows
Map management, output
Update or repair data source
Create a report
Build a variety of PDF map books

36. Manipulate map documents and layers
Add, remove and rotate data frames Add, remove layers Set properties
DATA FRAME
Referinta spatiala
Extend
Etc.
‘Curent’

37. Manipulate map documents and layers
Add, remove and rotate data frames Add, remove layers Set properties
LAYER
Name, Source, Label,
Visibility, Transparency
Etc.

38. SUMAR – GEOPROCESARE folosind ARCMAP si python
Geoprocessing is for everyone that uses ArcGIS. Whether you're a beginning user or a pro, geoprocessing will become an essential part of your day-to-day work with ArcGIS. The fundamental purposes of geoprocessing are to allow you to automate your GIS tasks and perform spatial analysis and modeling. Almost all uses of GIS involve the repetition of work, and this creates the need for methods to automate, document, and share multiple-step procedures known as workflows.

39. SUMAR – GEOPROCESARE folosind ARCMAP si python
Geoprocessing supports the automation of workflows by providing a rich set of tools and a mechanism to combine a series of tools in a sequence of operations using models and scripts. Geoprocessing is based on a framework of data transformation. A typical geoprocessing tool performs an operation on an ArcGIS dataset (such as a feature class, raster, or table) and produces a new dataset as the result of the tool. Each geoprocessing tool performs a small yet essential operation on geographic data, such as projecting a dataset from one map projection to another, adding a field to a table, or creating a buffer zone around features. ArcGIS includes hundreds of such geoprocessing tools.

40. MULTUMESC PENTRU ATENTIE 
DONE !
MULTUMESC PENTRU ATENTIE 