Arc Objects

1
Arc Objects

• Arc Objects is the development platform for the
  ArcGIS family of applications such as Arc Map,
  Arc Catalog, and Arc Scene.
• Arc Objects is a framework that lets you create
  domain-specific components from other components.
• Arc Objects provides an infrastructure for
• application customization that lets you
  concentrate on serving the specific needs of your
  clients.

2
ARCOBJECTS AND THE ARCGIS DESKTOP

• ArcObjects is the development platform for Arc
  GIS Desktop.
• The Arc GIS Desktop systems each contain a
  configuration of applications,such as Arc
  Catalog, Arc Map, Arc Toolbox, and Arc Scene, and
  can host a variety of extension products such as
  ArcGIS Spatial Analyst,ArcGIS Geostatistical
  Analyst, ArcGIS 3D Analyst and others.

3
Arc Map , Arc Catalog

• Arc Map is used for mapping and editing tasks as
  well as map-based analysis.
• Arc Catalog is used for managing your spatial
• data holdings, defining your geographic data
• custom schemas, and recording and viewing
  metadata.

4
ARCOBJECTS FRAMEWORK

• Arc Objects is built using Microsofts Component
  Object Model (COM) technology.
• It is possible to extend Arc Objects by writing
  COM components using any COM-compliant
  development language.
• You can extend every part of the Arc Objects
  architecture in exactly the same way as ESRI
  developers do.

5
Interpreting object model diagrams

• Arc Objects object model diagrams are based on
  the UML notation, an industry-diagramming
  standard for object-oriented analysis and design.
• The development environment,Visual Basic or
  other, lists all of the many classes and members
  but does not show the structure of those classes.
• These diagrams complete your understanding of
  the Arc Objects components.

6
Classes and objects

• There are 3 types of classes shown in the UML
  diagrams
• abstract classes, co classes, and classes.
• A coclass represents objects that you can
  directly create using the object declaration
  syntax in your development environment. In Visual
  Basic, this is written with the
• Dim pFoo As New FooObject syntax.
• A class cannot directly create new objects, but
  objects of a class can be created as a property
  of another class or by functions from another
  class. Eg. FeatureCursor
• An abstract class cannot be used to create new
  objects, but it is a specification for
  subclasses.Eg line could be an abstract class
  for primary line and secondary line

7
Type inheritance

• Type inheritance defines specialized classes that
  share properties and methods with the super class
  and have additional properties and methods.

Line
Primary Line
Secondary Line
This diagram shows that a primary line (creatable
class) and secondary line (creatable class) are
types of a line (abstract class).
8
Instantiation

• Instantiation specifies that one object from one
  class has a method with which it creates an
  object from another class.

Pole
Transformer
A pole object might have a method to create a
transformer object.
9
Customization

• Showing and hiding toolbars using the Customize
  dialog box
• 1. Click the Tools menu and click Customize.
• The Customize dialog box appears.
• You can also double-click any unoccupied area
  of any toolbar to display the Customize dialog
  box.
• 2. If it is not visible, click the Toolbars
  tab.
• The presence or absence of a check mark next
  to the toolbar name indicates its visible
  state.
• 3. Check and uncheck the check boxes.

10
Creating a new toolbar

• In the Toolbars tab of the Customize dialog box,
  click New.
• In the dialog box that appears, specify Chapter
  One Examples as the name of the new toolbar or
  use the default setting.
• Store the toolbar in the document by changing the
  name of the Save in dropdown list from Normal.mxt
  to Untitled or the name of the current project.
• Click OK.
• The newly created toolbar appears near the top of
  the application window.

11
Adding buttons to a toolbar

• Make sure the toolbar you just created is
  visible.
• If it is not visible, display the Customize
  dialog box.
• Click the Commands tab of the Customize dialog
  box.
• Select the Pan/Zoom category from the Categories
  list.
• Scroll to the bottom of the Commands list.
• Select the Zoom in command and drag it to the
  toolbar. Release the command when the arrow
  cursor with a small box below it appears.
• Continue adding commands from the Pan/Zoom
  category
• You may switch to other categories to select
  commands.
• Resize the toolbar so that its width allows the
  display of two commands per row.
• Note that you can dock the toolbar or drag it to
  any of the toolbar drop sites on the application
  window.

12
Renaming a toolbar

• In the Toolbars tab, click the name of the
  toolbar whose name you want to change.
• Click the Rename button.
• In the dialog box that appears, specify My Own
  Tools as the new name.
• Note that you can only rename toolbars youve
  created.
• Click OK.
• If you decide not to rename the toolbar, click
  Cancel.

13
Removing buttons from a toolbar

• Make sure the toolbar you just renamed, My Own
  Tools, is visible.
• If it is not visible, display the Customize
  dialog box.
• Drag some of the commands off the toolbar.
• Even though youve removed the buttons from the
  toolbar, they are still available in the
  Customize dialog box.

14
Adding a menu to a toolbar

• Make sure the My Own Tools toolbar is visible.
• If it is not visible, display the Customize
  dialog box.
• Click the Commands tab and choose the Menus
  category from the Categories list on the
  left-hand side of the dialog box.
• In the Commands list at the right-hand side of
  the dialog box, click Selection.
• Drag and drop it to the left of the Zoom In
  button on the My Own Tools toolbar.
• Click Close in the Customize dialog box.
• Click Selection on the My Own Tools toolbar and
  note the menu that appears.

15
Saving changes to a template

• You can save your work to a document or template.
  Changes saved to a document are specific to the
  document, whereas changes saved to a template
  will be reflected in all documents based on the
  template.
• Click the File menu and click Save As.
• Navigate to the Templates folder of the
  ltinstallation directorygt\bin folder.
• Click the Create New Folder button.
• Type a new name for the folder and double-click
  it.
• Type the template name, click ArcMap Templates
  (.mxt) from the Save as type dropdown menu, then
  click Save.

16
WRITING MACROS IN VBA

• You can use the VBA integrated development
  environment to create macros to help you automate
  tasks you perform repeatedly or to extend the
  applications built-in functionality.
• With the Visual Basic Editor, you can edit
  macros, copy macros from one module to another,
  rename the modules that store the macros, or
  rename the macros.

17
Creating a macro

• Click the Tools menu, point to Macros, then click
  Macros.
• In the Macros dialog, type name in the Macro
  name text box and click Create.
• The application creates a new module named
  Module1 and stubs in the Sub procedure.
• Enter some code.
• Switch back to ArcMap by clicking the File menu,
  clicking Close, and clicking Return to ArcMap.
• Click the Tools menu, point to Macros, then click
  Macros.
• Select the Module1. Name macro and click Run.

18
Adding a macro to a toolbar

• Click the Tools menu and click Customize.
• In the Toolbars tab, ensure that the toolbar is
  visible.
• Click the Commands tab and select the Macros
  category.
• Click the name of project in the Save in
  dropdown menu.
• The commands list to the right of the dialog box
  lists Project.Module1.Name.
• Drag the macro name to the toolbar you created.
• The macro appears with a default icon.
• To change its properties, right-click the icon.
• In the context menu that appears, click Change
  Button Image and choose a button from the palette
  of icons.
• Close the Customize dialog box.
• Click the button to run the macro.

19
Calling built-in Commands

• Calling existing commands involves working with
  the ArcID module.
• Using the Find method, the code locates the
  unique identifier (UID) of the command in the
  ArcID module.
• Steps
• 1. Click the Tools menu, point to Macros, then
  click Visual Basic Editor.
• 2. In the Module1 module, create a Sub
  procedure with the following code
• 3. Add the macro to a toolbar or menu.
• 4. Run the macro.

20
Code for FullExtent

• Sub FullExtentPlus()
• Dim intAns As Integer
• Dim pItem As ICommandItem
• With ThisDocument.CommandBars
• Set pItem .Find(ArcID.PanZoom_FullExtent)
• pItem.Execute
• intAns MsgBox(Zoom to previous extent?,
  vbYesNo)
• If intAns vbYes Then
• Set pItem .Find(ArcID.PanZoom_ZoomToLastExten
  tBack)
• pItem.Execute
• End If
• End With
• End Sub

21
Creating a Command in VBA

• Once invoked, a command usually performs some
  direct action without user intervention.
• A command is a type of UIControl.
• Click the Tools menu and click Customize.
• In the Customize dialog box, click the Commands
  tab and change the Save in dropdown menu to the
  name of your project or to Untitled.
• In the Categories list, select UIControls.
• Click New UIControl.
• In the dialog box that appears, choose
  UIButtonControl as the UIControl Type, then click
  Create and Edit.

22
Adding code for the UIControl

• The application adds an entry in the Object Box
  for the UIButtonControl and stubs in an event
  procedure for the UIButtonControls Click event.
• Youll add code to this event to zoom the display
  to the extents of the dataset.
• Private Sub UIButtonControl1_Click()
• Dim pDoc As IMxDocument
• Set pDoc ThisDocument
• pDoc.ActiveView.Extent pDoc.ActiveView.FullExten
  t
• pDoc.ActiveView.Refresh
• End Sub

23
Adding code for the UIControl

• Click the Tools menu, click Customize, then click
  the Commands tab.
• In the Customize dialog box, click the Commands
  tab and change the Save in dropdown menu to the
  name of your project or to Untitled.
• In the Categories list, choose UIControls and
  drag the UIButtonControl you created to a
  toolbar. Close the Customize dialog box.
• Try the new command by zooming in on the map and
  clicking the button.

24
Creating a tool in VBA

• 1. Click the Tools menu and click Customize.
• 2. Click the Commands tab and change the Save in
  combo box to the name of your project or
  Untitled.
• 3. Choose UIControls from the Categories list.
• 4. Click New UIControl.
• 5. In the dialog box that appears, choose
  UIToolControl as the UIControl Type, then click
  Create and Edit.

25
Changing button properties

• Right-click any toolbar and click Customize in
  the context menu that appears. Click the right
  mouse button to determine whether a context menu
  is available.
• Right-click the button whose properties you want
  to change.
• In the context menu that appears, click Change
  Button Image and choose an image. The image you
  chose appears on the face of the button.
• Close the Customize dialog box.

26
Thank you..
27
Arc Objects Problem Solving Guide

• DEFINE THE ARCOBJECTS PROGRAMMING TASK
• 1. Describe the problem in Arc Objects terms.
• 2. Identify subtasks.
• 3. Decide where to write the code.
• 4. Search for a related sample or recommended
  methodology.
• LOCATE THE CORRECT OBJECT MODEL
• 1. Identify a subtask.
• 2. Extract keywords.
• 3. Search for the correct object model diagrams.
• 4. Review all related documentation.
• NAVIGATE THE OBJECT MODEL DIAGRAM
• 1. Review the structure of the object model
  diagram.
• 2. Trace the flow between classes and assemble
  code.

28
Writing Code Using Arc Objects

• In general, there are three ways to write Arc
  Objects code
• As a VBA macro in an ArcGIS application
• As an ActiveX COM component such as a DLL or
  OCX
• As a standalone EXE

29
Writing VBA macros in ArcGIS

• Advantages
• Its fast and easy to create, test, and debug
  macros inside Arc Map and Arc Catalog.
• The standard ESRI type libraries are already
  referenced.
• Important global variables, such as the
  Application and Document, are available.
• Its simple to assemble UI forms using VBA
  and ActiveX components.
• Its straightforward to integrate VBA code
  with new Arc Objects UIControls.
• Its relatively easy to migrate VBA code to
  VB ActiveX DLL projects.

30
Writing ActiveX COM components

• Advantages
• They can be easily delivered to end users via
  custom setup programs.
• You can hide Arc Objects code in a binary file
  and then deliver the functionality to end users
  with a setup program.
• You can extend and customize virtually every
  aspect of the ArcGIS technology.
• Disadvantages
• Have to acquire and use another COM-compliant
  development tool
• Do not have direct access to the Application
  and ThisDocument global variables.
• It is often more difficult to debug the code.

31
Standalone Applications

• Advantages
• You can use the ESRI Arc Objects Map control
  to simplify the embedding of Arc Objects
  functionality in your application.
• You can design a highly customized user
  interface specific to your application.
• You can quickly create small, lightweight
  applications.
• Disadvantages
• You cannot take advantage of the extensive
  functionality that ESRI has built into the
  existing ArcGIS applications such as Arc Map or
  Arc Catalog.
• You cannot use Arc Map documents or templates
  to their fullest capacity.
• None of the extensions, including the Editor,
  can be used.

32
Arc Map Core Objects
33
Arc Map Document
34
APPLICATION COCLASS

• The Application object directly manages a
  collection of objects, MxDocument,
  AppDisplay,SelectionEnvironment.
• When you first start Arc Map, the Application
  object is first created, and then it in turn
  instantiates all of the objects it manages.
• The IApplication interface provides access to the
  MxDocument object, the StatusBar object, the
  Templates object, the currently selected tool,
  the Visual Basic Editor.
• The IMxApplication interface provides access to
  the remainder of the objects the Application
  automatically creates, including AppDisplay,Paper
  Co Class, Printer, and SelectionEnvironment.
  Additionally, IMxApplication exposes methods for
  exporting the current map document or copying it
  to the system clipboard.

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36
MXDOCUMENT COCLASS

• The Arc Map document is called MxDocument its
  role is to control the representation of data.
• The Arc Map application automatically creates
  this object when the application first starts.
• MxDocument specifically creates and manages the
  following objects an empty Map, a PageLayout,
  the TOCCatalogView, the TOCDisplayView.
• You can obtain a reference to the MxDocument
  through IApplicationDocument.

37
Views

• View is the main application window, or the place
  where all data is drawn.
• Arc Map currently has two different views,data
  view and layout view
• Objects implement the IActiveView interface to
  establish themselves as views.
• The data view corresponds to a Map object, and
  the layout view corresponds to the PageLayout
  object.
• Either of these objects can be set as the
  documents active view, and only one view is
  visible at a time.

38
Checking Type of View

• The following VBA code checks the type of active
  view
• Dim pMxDoc As IMxDocument
• Set pMxDoc Application.Document
• If TypeOf pMxDoc.ActiveView Is IMap Then
• MsgBox "Active View is a Map"
• ElseIf TypeOf pMxDoc.ActiveView Is IPageLayout
  Then
• MsgBox "Active view is the PageLayout"
• End If

39
Application Extensions

• The Application object directly manages the life
  of all application extensions.
• Application extensions are those extensions
  registered in the ESRI MxExtension objects
• All extensions are automatically created and
  destroyed in synchronization with an Application
  object.
• Use the IExtension interface to query the
  properties of an extension or implement this
  interface to create your own custom extension.

40
Getting Reference to an Extension

• Public Sub CheckEditState()
• Dim pEditor As IEditor
• Dim pUID As New UID
• pUID "esriCore.Editor"
• Set pEditor Application.FindExtensionByCLSID(pU
  ID)
• If pEditor.EditState esriStateEditing Then
• MsgBox "Active Edit Session Present"
• End If
• End Sub

41
TOCDISPLAYVIEW AND TOCCONTENTSVIEW COCLASSES

• Contents views are tabs in the Arc Map table of
  contents.
• ArcMap ships with two contents views display
  view and source view.
• The Display tab is the TOCDisplayView object, and
  the Source tab is the TOCCatalogView object.
• Developers can add new contents views by
  creating their own custom object that implements
  the IContentsView interface.

42
MAP COCLASS

• Every map document contains at least one Map
  object.
• Only one Map can have focus at a time, and this
  Map is called the focus map.
• IMxDocument provides access to all of the Map
  objects loaded in the document
• IMxDocumentFocusMap returns a reference to the
  Map currently with focus, and IMxDocument.Maps
  returns the entire collection of Map objects.
• MapSurround objects are elements that are related
  to a Map. Types of map surrounds include Legends,
  NorthArrows, and ScaleBars.

43
SELECTIONENVIRONMENT COCLASS

• Controls properties related to creating and
  drawing selections.
• A SelectionEnvironment object is automatically
  created by the Application object when the
  application starts.
• Access to the Application objects
  SelectionEnvironment is through
  IMxApplicationSelectionEnvironment.

44
Change Default Selection Color

• Public Sub ChangeDefaultSelectionColor()
• Dim pMxDoc As IMxDocument
• Dim pMxApp As IMxApplication
• Dim pSelectionEnv As ISelectionEnvironment
• Dim pRgbColor As IRgbColor
• Set pMxApp Application 'QI
• Set pMxDoc Application.Document
• Set pSelectionEnv pMxApp.SelectionEnvironment
• Set pRgbColor New RgbColor
• pRgbColor.Red 255
• Set pSelectionEnv.DefaultColor pRgbColor
• End Sub

45
Display Objects

• FEATURE RENDERER
• A feature renderer is a method for drawing
  feature layers.
• Use symbols and colors to visually display
  features, possibly based on one or more
  attributes.
• Types of feature renderers
• SimpleRenderer uses the same symbol for each
  feature.
• ClassBreaksRenderer allows classes of numeric
  attribute values to be defined. A different
  symbol is specified for each class.
• UniqueValueRenderer uses a different symbol
  for each unique attribute value.
• ProportionalSymbolRenderer modifies the size
  of the symbol in proportion to an attribute from
  a field.
• DotDensityRenderer displays a scattering of
  marker symbols in polygon features, the density
  of which reflects the value of an attribute.
• ChartRenderer displays pie, bar, or stacked
  bar charts that are comprised from one or more
  attribute fields.
• ScaleBreaksRenderer switches renderers
  depending on the map viewing scale.

46
Get a Feature Renderer

• To get to a feature renderer object in Arc Map
  from a layer, QI to IGeoFeatureLayer and get the
  Renderer property.
• A simple renderer is the default renderer object
  when a new feature class is loaded.
• ' Check if the layer is a feature layer
• If Not TypeOf pLayer Is IGeoFeatureLayer Then
  Exit Sub
• Set pGeoFeatureLayer pLayer
• ' Check if there is a simple renderer and get a
  reference to it
• If Not TypeOf pGeoFeatureLayer.Renderer Is
  ISimpleRenderer Then Exit Sub
• Set pSimpleRenderer pGeoFeatureLayer.Renderer

47
Color Objects

• Objects that support the IColor interface allow
  precise control over any color used within the
  ArcObjects model.
• You can get and set colors using a variety of
  standard color modelsRGB, CMYK, HSV, HLS, and
  Grayscale.
• RGBCOLOR COCLASS
• To get and set the red,green, and blue
  components of a color
• Interface- IRGBColor
• CMYKCOLOR COCLASS
• Colors can be specified for output in terms of
  Cyan, Magenta, Yellow, and Black.
• Interface- ICMYKColor

48
Symbol Objects
49
Types of Symbols

• ArcObjects uses three categories of symbols to
  draw geographic features
• Marker symbols,
• Line symbols,
• Fill symbols.

50
Display Objects
51
Display Objects

• Allow application developers to easily draw
  graphics on a variety of output devices.
• Allow you to render shapes stored in real-world
  coordinates to the screen, the printer, and
  export files.
• Use the IDisplay interface to draw points, lines,
  polygons, rectangles,and text on a device.
• Access to the display objects DisplayTransformati
  on object is provided by this interface.

52
To Pan Map Display

• Private Sub UIToolControl1_MouseDown(ByVal button
  As Long, _ByVal shift As Long, ByVal x As Long,
  ByVal y As Long)
• Dim pScreenDisplay As IScreenDisplay
• Dim pActiveView As IActiveView
• Dim pMxDoc As IMxDocument
• Set pMxDoc Application.Document
• Set pActiveView pMxDoc.FocusMap
• Set pScreenDisplay pActiveView.ScreenDisplay
• pScreenDisplay.TrackPan
• End Sub

53
DISPLAYTRANSFORMATION COCLASS

• Manages the map-to-device transformation
• Defines how real-world coordinates are mapped to
  an output space.
• Maps DisplayTransformation has a
  SpatialReference
• object that manages the Maps current coordinate
  system.
• A reference to the SpatialReference object is set
  through IDisplayTransformationSpatialReference.

54
IDisplayTransformation

• To prepare a transform for use, follow these
  steps
• 1. Set the full map extent with the Bounds
  property.
• 2. Set the visible map extent (zoom rectangle)
  with the VisibleBounds property.
• 3. Set the output area of the device using the
  DeviceFrame property.
• 4. Set the resolution of the output device using
  the Resolution property.

55
Rubber Band Objects
56
IRubberBand Interface

• IRubberBand interface, allow the user to digitize
  geometries on the display using the mouseeither
  to create whole new geometry objects or to update
  existing ones.
• Examples-Dragging an envelope, forming a new
  polyline, or moving a point.
• IRubberband interface has two methods
• TrackExisting
• Move existing geometries
• TrackNew
• Create new geometries

57
TrackNew method

• Private Sub UIToolControl1_MouseDown(ByVal button
  As Long, _
• ByVal shift As Long, ByVal x As Long, ByVal y As
  Long)
• Dim pRubberLine As IRubberBand
• Dim pGeom As IGeometry
• Dim pMXDoc As IMxDocument
• Set pMXDoc ThisDocument
• Set pRubberLine New RubberLine
• Set pGeompRubberLine.TrackNew
• (pMXDoc.ActiveView.ScreenDisplay, Nothing)
• End Sub