Advanced GIS GEOG 48505850 TTU

1
Advanced GISGEOG 4850/5850TTU

• Week 2, 2003 Fall

2
Characteristics of Objects

• Object Properties Actions State
• Car make start direction north
• model stop speed 75 mph
• color turn left
• 4 doors turn right

Objects defined as a person, place, or thing
that knows the values of its attributes and can
perform operations on those attributes. Called
Class instances and operations are also called
methods or services.
3
Class and Objects
Classes a class groups objects based on common
characteristics. For example, a display extent
object belongs to the rectangle class, and an
individual belongs to the human class
All objects of a class share the same attribute
types and operations

• Car Class

View Class
View 1
View 2
View 3
4
Class Relationship

• Inheritance
• Aggregation
• Association

Two types of classes abstract and concrete.
Abstract classes do not instantiate objects,
while their descendants have objects. For
example, consider the class Doc, which has no
objects, but its descendant classes, such as View
and Chart, do have objects. Therefore, Doc is an
absbract class while View and Chart are concrete
classes.
5
Inheritance

• is a kind of relationship

Car
Pickup
Sedan
Van
Convertible
4X4
6
Aggregation

• is composed of relationship

Project
Car
Engine
Radio
Tire
Script
View
Table
Tuner
CD
TOC
Theme
7
Association

• Link between two classes or objects

Runs on
Gasoline
Car
DocWin
Doc
Is viewed through Displays
8
Requests

• Make things happen in ArcView
• Class Request - create a new object, e.g. create
  a new theme.
• Instance Request - retrieve or modify existing
  objects, e.g. show/hide legend
• Different classes support different requests.
  Views accept request for zooming, but not tables
• Polymorphism - similar request for different
  objects, e.g. Make View or Table.

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Request Forms

• Request begins with a Verb, e.g. GetProject,
  FindScript, AddDoc where Get, Find and Add are
  actions and Project, Script and Doc receive that
  Action
• Request with arguments
• some requests require additional information, or
  argument
• eg. theView theProject.FindDoc(United
  States)

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Action keyword

• Add
• As
• Can
• Find
• Get
• Has
• Is
• Make
• Return
• Set

• Include another object in a
• group of objects
• Convert an object to an object
• of a different class
• check if the object can perform
• the specified function
• search for the specified object
• and return a reference to it
• return a reference to an object
• indicate if the object has the
• specified condition or state
• return true or false
• create a new instance
• create a new object and return
• a reference to it
• assign an attribute of an object

• aView.AddTheme(myTheme)
• aNumber.AsString
• aTheme.CanEdit
• aView.FindTheme(Roads)
• aView.GetTheme
• aScript.HasError
• aButton.IsVisible
• View.Make
• aFileName.ReturnDir
• aButton.SetIcon

11
Naming Variables

• Long enough to indicate the purpose
• Avoid the class names, such as View, theme.
  Instead, use aView, myTheme, etc.
• Always favor using local variables
• Make the first character lowercase
• Consistence
• Getting Started
• application object - av plus a request
• eg. theProject av.GetProject
• This Object.Request returns the current project.
  The next thing you need to do is finding the view
  within the project, and this can be done by
  typing in
• theViewtheProject.FindDoc(United States)

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Requests Execution

• Object.Request
• Postfix notation - theView.Print
• Infix notation - 101 662
• Prefix notation - not someCondition, but you may
  still use Postfix notation for this request -
  someCondition.not
• Return of another object - theName
  theView.GetName
• myNumber 2 5
• Simplify your requests
• theProject av.GetProject
• theView the Project.FindDoc (World)
• theTheme theView.FindTheme (Major Cities)
• the following is the combination of the previous
  three lines of codes
• theTheme av.GetProject.FindDoc(World).FindThe
  me(Major Cities)

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Message Box (MsgBox.)

• Message box displays information, error and
  warning messages to viewers and sometimes provide
  selections and choices and return values to the
  variables. Many requests follows the MsgBox have
  various functions (Info, YesNo, choices)
• Now, open a new project and come to Scripts in
  TOC and double-click on Script to bring on the
  Script window. ProjectPropertiesStartUp (see
  demo)
• Type in the following script and have it attached
  to the StartUp property in
• MsgBox.Info (Welcome to my first script, Hello
  World)
• Click on Compile and Run

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• Error message box
• MsgBox.Error (Unable to open file,). If no
  title passed onto message box, Error is the
  default title.

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Welcome/Shutdown

• Remember save the scripts name as A1.Welcome
  and have it compiled before you send it to the
  Startup box.
• Now create another shutdown script for the
  Shutdown and save your project as
  a1.ShutDownMsg in your folder
• close project
• aProject av.GetProject
• MsgBox.Info(This will close your project without
  saving it, Close Project)
• aProject.Close
• Exit program
• MsgBox.Info(This will end your program without
  saving it, Exit Program)
• Av.Quit

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Exercise

• Design a message box with title Where you want
  to go during Fall Break? and MultiListAsString
  request for the places like Japan,
  Mexico,France, Greece
• MsgBox.MultiListAsString(stringOption, text on
  msg,Title)
• Create a new button in the View and assign a new
  icon and have the message box associated with
  this button.
• If ... structure
• If.... then
• elseif... then
• elseif... then
• else
• end

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Options - try this
Notes use Object.Get(0) object.Get(1)..... to
indicate the names selected by the user
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Right here!!!!

• 'MultiListAsString, Country
• options "Japan", "Mexico", "France", "Greece"
  
• choices MsgBox.MultiListAsString( options,
  "Select some", "SELECT" )
• if (choices nil) then
• MsgBox.Info( "NO SELECTION", "No Selection
  Message")
• end
• Count choices.count
• if (Count 4) then
• MsgBox.Info("You have selected"
  choices.Get(0) ","choices.Get(1)","choic
  es.Get(2)"and"choices.Get(3),"Select"choices
  .count.AsString)
• elseif (Count 3) then
• MsgBox.Info("You have selected"
  choices.Get(0) ","choices.Get(1)"and"cho
  ices.Get(2),"Select 3")
• elseif (Count 2) then
• MsgBox.Info("You have selected"
  choices.Get(0) "and"choices.Get(1),"Select
  2")
• else
• MsgBox.Info( "You have selected"
  choices.Get(0),"How Many")
• end

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Now try this
Use ChoiceAsString China,France and Mexico
If (expression) then statement
statement elseif statement else end
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Solution

• myList "China","France","Mexico",
  "Japan","US","Korea"
• YourChoice MsgBox.ChoiceAsString(myList,"Choose
  your destination","Where to go")
• if (YourChoice "China") then
• MsgBox.Info ("You must like Chinese
  food","Dragon")
• elseif (YourChoice "France") then
• MsgBox.Info("How about frog meat?","Bonjo")
• elseif (YourChoice "Japan") then
• MsgBox.Info("Sashimi is good","Sumo")
• elseif (YourChoice "US") then
• MsgBox.Info("Hamburger", "McDonald")
• elseif (YourChoice"Korea") then
• MsgBox.Info("KimGee","BinBinBo")
• else
• MsgBox.Info("Bean Eater","Amigo")
• end

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Data Types

• string - delimited with the double quote, eg -
  myString Hello Everyone
• Concatenate two strings with or (with one
  space bet/w strings)
• Insert a newline bet/w 2 strings, myString
  Hello NL How are you?
• AsFileName, AsList,,,,
• Extract, LCase, Left, Middle, Proper, Right,
  Translate, Trim and UCase

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Dates

• yyear from 1 to 99
• yy year from 01 to 99
• yyyy year with century
• MMonth from 1 to 12
• MM Month from 01 to 12
• MMMMonths name
• MMMMMonths name
• d day from 1 to 31
• dd day from 01 to 31
• dddshort form of the days name
• dddd days name

• m minute from 00 to 59
• s second from 00 to 59
• h hour from 1 to 12
• hh hour from 01 to 12
• hhh hour from 0 to 23
• hhhh hour from 00 to 23
• AMPM Am or PM string
• TZ Time zone string

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Date usage

• yesterday Date.Now - (1.AsDays)
• yesterday.SetFormat(dddd MMMM, yyyy)
• MsgBox.Info (Yesterday was
  yesterday.AsString, )
• Exercise Print Next Thursdays date using MsgBox
  and SetFormat

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Using Booleans

• aTrueObj true
• aFalseObj false
• iAmYounger (myBirthDay yourBirthDay)
• MsgBox.Info(iAmYounger.AsString, )
• Exercise
• Type in todays date, and see your answer is
  correct or not.
• myDate MsgBox.Input(

25
Using Enumerations

• Create a character field as follows
• newField Field.Make (Last_Name, FIELD_CHAR,
  40,0)
• The FIELD_CHAR is the enumeration that specifies
  character field type.
• All enumeration start with the pound sign

26
Using Nil

• Non-existence of object - a nil object, such as
  the follows
• myView av.GetProject.FindDoc (View1)
• if (myView nil) then
• MsgBox.Error(View1 does not exist, )
• end
• Nil is different from null. Some objects may be
  null (no value)
• Test null by using the IsNull request.

27
Local/Global Variables

• Local - used within the script
• Global - accessed beyond the current script.
  Share objects between scripts
• Mostly use local variable
• Global variable (starts with an underscore_)
• _theProject av.GetProject
• The memory allocated to global variables must be
  cleared by
• av.ClearGlobals
• Global variable has to be initialized before
  compiling a script

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• Using Object Tags
• Object tag alternative to using global
  variables.
• aTheme.SetObjectTag(Alias Name) tag object
• aliasName aTheme.GetObjectTag retrieve object
• Using Lists
• Avenue provides several classes of collections
  (collections are objects that contain other
  objects)
• Collections are useful in organizing related
  information. For instance, it is easier to keep
  the names of all your themes in a list called
  allMyThemes than scattered among many different
  variables.
• Lists are series of objects created through
  direct assignment or by request.

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List Example

• 'List Example
• roadClass "LIGHT","MEDIUM","HEAVY"
• roadClass.Add ("DAMAGED")
• 'roadClass list is composed of LIGHT,MEDIUM,
  HEAVY, and DAMAGED string objects
• roadAnnualCost List.Make
• 'The Add request appends an object to the end of
  a list.
• roadAnnualCost.Add (25000)
• 'The Insert request places an object on the top
  of a list.
• roadAnnualCost.Insert(12000)
• lightRoadAnnualCost roadAnnualCost.Get(0)
• 'The variable lightRoadAnnualCost references
• 'the number object 12000
• MsgBox.MultiListAsString(roadClass,"roadClass","")

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Dictionary

• is an efficient method to store and retrieve
  objects. In concept, they are similar to a
  two-column table with identifier and value column
  headings. Any type of object can be stored by a
  key, and the key may be from any class.
• Try to access dictionary using Get(0), Get(1). It
  does not reference to the sequence of the
  dictionary. List is more efficient for
  sequential access

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Example-dictionary

• roadTravelCost Dictionary.Make(2)
• '(2) refers to the size of hash tables not number
  of objects in the dictionary. The number of
  objects should not exceed hash size times 20.
• roadTravelCost.Add("HEAVY",35.48)
• roadTravelCost.Add("MEDIUM",35.00)
• roadTravelCost.Add("LIGHT",34.28)
• roadTravelCost.Add("GRAVEL",35.50)
• graveRoadCost roadTravelCost.Get("GRAVEL")
• 'The variable gravelRoadCost references
• 'the number object 35.50 write a msgbox to show
  the value
• 'use AsString to convert number to string
• 'MsgBox.Info(roadTravelCost.Get(2).AsString,"")
• MsgBox.Info(roadTravelCost.Get("GRAVEL").AsString,
  "")

32
Using Intervals and Duration

• Objects of intervals class model a range of
  numbers with a defined set of subdivisions.
  Intervals are often used to construct a For Each
  loop. If the loop requires iterating through a
  range of numbers in equal increments, an interval
  is more efficient than a list of numbers.
• oddInterval 1..9 by 2
• for each oddDigit in oddInterval
• MsgBox.Info(Odd digit
  oddDigit.AsString, )
• end

33
Using Duration

• default duration is one second
• This script creates and displays a list of
  Wednesday in 2002
• wednesdayInterval (20020102.AsDate)..(20020504.A
  sDate) by 7.AsDays
• wednesdayList
• for each wednesday in wednesdayInterval
• wednesdayList.Add(wednesday)
• end
• MsgBox.ListAsString (wednesdayList,Wednesday in
  Spring Semester, )

34
Using Bitmaps

• Bitmaps are collections of Boolean values. They
  are similar to lists except that each element is
  a Boolean object. Although you can create a
  bitmap with a Make request, you typically work
  with the existing bitmaps. ArcView uses bitmaps
  to identify spatial or attribute records that are
  selected or defined as part of a query.

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Object, variables

• ArcView treats things like numbers and text
  strings as objects as well.
• MsgBox.Info(The view name is aViewName,
  Name)
• Requests will return another object or not, e.g.
  theTheme.SetVisible(true), theProject
  av.GetProject
• You might use variable (global/local) to
  reference the objects.
• _theProject av.GetProject (global v)

36
Tools or Buttons

• Button - Zoom in,
• Tool - Zoom in Tool.
• Tool has an additional property besides Click,
  Apply. It runs the script associated with it
  when applied to the active document

37
Click/Apply Scripts

• Script associated with Zoom In Buttons Click
  property
• av.GetProject.SetModified(true)
• theView av.GetActiveDoc
• theView.GetDisplay.ZoomIn(125)
• Script associated with ZoomIn Tools Apply
  property
• av.GetProject.SetModified(true)
• theView av.GetActiveDoc
• r theView.ReturnUserDoc
• d theView.GetDisplay
• if (r.IsNull) then
• d.ZoomIn(125)
• d.PanTo (d.ReturnUserPoint)
• else
• d.ZoomToRect(r)
• end

38
Interacting w/ Other Appl.

• RPC - all platforms
• DDE - windows
• DDL - windows
• AppleEvents/AppleScript

39
Customizing ArcView User Interface

• Start a new project
• Select Project/Customize menu
• Set Category to Menu, type to Appl
• In File, make New Project menu invisible

40
Application Framework

• The only instance of the Application class is the
  ArcView program, which can be accessed in Avenue
  through the keyword av. You can access almost
  all objects in ArcView from av because it
  contains all the objects that comprise ArcView.
  You can change the default name for ArcView GIS
  3.2a to any name you want by using
  av.SetName(Any Name Here)

system default
Project
Application
Extension
Script
DocGUI
Doc
DocWin
View
Table
Chart
Layout
SEd
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Turn on/off the themes (open C\ESRI\AV_GIS30\AVT
UTOR\ARCVIEW\qstart.apr)

• theProject av.GetProject
• theView theProject.FindDoc(United States)
• get the list of themes in the view
• theThemeList theView.GetThemes
• for each thm in theThemeList
• turn each theme on if off, and off if on
• if (thm.IsVisible) then
• thm.SetVisible(false)
• else
• thm.SetVisible(true)
• end if...then...else statement
• end for each statement
• theView.Invalidate

Start a new script and type in the codes
thm.SetVisible(thm.IsVisible.Not)
42
Now, try this on your script window

• for each x in 1..10 by 1
• MsgBox.Info("The numbe is"x.AsString, "What's
  the number")
• end

43
Replace If..then..else with for each...

• theProject av.GetProject
• theView theProject.FindDoc(United States)
• get the list of themes in the view
• for each thm in theView.GetThemes
• thm.SetVisible(thm.IsVisible.Not)
• end for each statement

Can be replaced with av.GetActiveDoc
44
Message Box

• Use message boxes to display information or
  accept user input
• aRegionMsgBox.ListAsString(North,South,East
  ,West,Choose a region,County Database)
• MsgBox.Info(aRegion Region,Loading...)

45
ListAsString(request)

• Allow the user to select an object from aList.
  This request displays a scrolling list box of
  strings obtained by sending the AsString request
  to each object in aList. Use this request
  (instead of MsgBox.List) for lists that include
  "immutable" objects such as strings, numbers, or
  boolean values. This request returns the selected
  object or nil if the user clicks CANCEL.
• Syntax
• MsgBox.ListAsString (aList, aMsg, aTitle)

46
This is what we got
after selected West
47
Errors
Syntax Error a 4 b3 if b less than 4, Example) end
Run-time Error a 4 b3 a MsgBox(bAsString
is the result, Example)
Logic Error a Lake bForest aStrMsgBox.Inpu
t(Enter the theme you want to load, Load
Theme,) If (aStr Lake) and (aStrForest)
then do something end
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Error Checking

• theView av.GetActiveDoc
• get the list of themes in the view
• if (theView.GetThemes.Count0) then
• MsgBox.Error(No themes in the view.,Cannot
  toggle themes)
• exit
• end
• for each thm in theView.GetThemes
• thm.SetVisible(thm.IsVisible.Not)
• end for each statement

49
Tool or button?

• button acts immediately, such as Zoom In button.
• tool - remains depressed when its clicked, but
  usually nothing happens until you click somewhere
  in the active document, such as Zoom In Tool.
• Tools has Apply property other than Click
  Apply is associated with scripts not click in
  tool

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• av.GetProject.SetModified(true)
• theViewav.GetActiveDoc
• theView.GetDisplay.ZoomIn(125)
• av.GetProject.SetModified(true)
• theViewav.GetActiveDoc
• rtheView.ReturnUserRect
• dtheView.GetDisplay
• if (r.IsNull) then
• d.ZoomIn(125)
• d.PanTo(d.ReturnUserPoint)
• else
• d.ZoomToRect(r)
• end

ZoomIn button
ZoomIn Tool